creation_sourcecode: // File: @openzeppelin/contracts/utils/Address.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (utils/Address.sol)
  
  pragma solidity ^0.8.20;
  
  /**
   * @dev Collection of functions related to the address type
   */
  library Address {
      /**
       * @dev The ETH balance of the account is not enough to perform the operation.
       */
      error AddressInsufficientBalance(address account);
  
      /**
       * @dev There's no code at `target` (it is not a contract).
       */
      error AddressEmptyCode(address target);
  
      /**
       * @dev A call to an address target failed. The target may have reverted.
       */
      error FailedInnerCall();
  
      /**
       * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
       * `recipient`, forwarding all available gas and reverting on errors.
       *
       * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
       * of certain opcodes, possibly making contracts go over the 2300 gas limit
       * imposed by `transfer`, making them unable to receive funds via
       * `transfer`. {sendValue} removes this limitation.
       *
       * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
       *
       * IMPORTANT: because control is transferred to `recipient`, care must be
       * taken to not create reentrancy vulnerabilities. Consider using
       * {ReentrancyGuard} or the
       * https://solidity.readthedocs.io/en/v0.8.20/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
       */
      function sendValue(address payable recipient, uint256 amount) internal {
          if (address(this).balance < amount) {
              revert AddressInsufficientBalance(address(this));
          }
  
          (bool success, ) = recipient.call{value: amount}("");
          if (!success) {
              revert FailedInnerCall();
          }
      }
  
      /**
       * @dev Performs a Solidity function call using a low level `call`. A
       * plain `call` is an unsafe replacement for a function call: use this
       * function instead.
       *
       * If `target` reverts with a revert reason or custom error, it is bubbled
       * up by this function (like regular Solidity function calls). However, if
       * the call reverted with no returned reason, this function reverts with a
       * {FailedInnerCall} error.
       *
       * Returns the raw returned data. To convert to the expected return value,
       * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
       *
       * Requirements:
       *
       * - `target` must be a contract.
       * - calling `target` with `data` must not revert.
       */
      function functionCall(address target, bytes memory data) internal returns (bytes memory) {
          return functionCallWithValue(target, data, 0);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but also transferring `value` wei to `target`.
       *
       * Requirements:
       *
       * - the calling contract must have an ETH balance of at least `value`.
       * - the called Solidity function must be `payable`.
       */
      function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
          if (address(this).balance < value) {
              revert AddressInsufficientBalance(address(this));
          }
          (bool success, bytes memory returndata) = target.call{value: value}(data);
          return verifyCallResultFromTarget(target, success, returndata);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a static call.
       */
      function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
          (bool success, bytes memory returndata) = target.staticcall(data);
          return verifyCallResultFromTarget(target, success, returndata);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a delegate call.
       */
      function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
          (bool success, bytes memory returndata) = target.delegatecall(data);
          return verifyCallResultFromTarget(target, success, returndata);
      }
  
      /**
       * @dev Tool to verify that a low level call to smart-contract was successful, and reverts if the target
       * was not a contract or bubbling up the revert reason (falling back to {FailedInnerCall}) in case of an
       * unsuccessful call.
       */
      function verifyCallResultFromTarget(
          address target,
          bool success,
          bytes memory returndata
      ) internal view returns (bytes memory) {
          if (!success) {
              _revert(returndata);
          } else {
              // only check if target is a contract if the call was successful and the return data is empty
              // otherwise we already know that it was a contract
              if (returndata.length == 0 && target.code.length == 0) {
                  revert AddressEmptyCode(target);
              }
              return returndata;
          }
      }
  
      /**
       * @dev Tool to verify that a low level call was successful, and reverts if it wasn't, either by bubbling the
       * revert reason or with a default {FailedInnerCall} error.
       */
      function verifyCallResult(bool success, bytes memory returndata) internal pure returns (bytes memory) {
          if (!success) {
              _revert(returndata);
          } else {
              return returndata;
          }
      }
  
      /**
       * @dev Reverts with returndata if present. Otherwise reverts with {FailedInnerCall}.
       */
      function _revert(bytes memory returndata) private pure {
          // Look for revert reason and bubble it up if present
          if (returndata.length > 0) {
              // The easiest way to bubble the revert reason is using memory via assembly
              /// @solidity memory-safe-assembly
              assembly {
                  let returndata_size := mload(returndata)
                  revert(add(32, returndata), returndata_size)
              }
          } else {
              revert FailedInnerCall();
          }
      }
  }
  
  // File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Permit.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Permit.sol)
  
  pragma solidity ^0.8.20;
  
  /**
   * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
   * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
   *
   * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
   * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
   * need to send a transaction, and thus is not required to hold Ether at all.
   *
   * ==== Security Considerations
   *
   * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
   * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
   * considered as an intention to spend the allowance in any specific way. The second is that because permits have
   * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
   * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
   * generally recommended is:
   *
   * ```solidity
   * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
   *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
   *     doThing(..., value);
   * }
   *
   * function doThing(..., uint256 value) public {
   *     token.safeTransferFrom(msg.sender, address(this), value);
   *     ...
   * }
   * ```
   *
   * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
   * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
   * {SafeERC20-safeTransferFrom}).
   *
   * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
   * contracts should have entry points that don't rely on permit.
   */
  interface IERC20Permit {
      /**
       * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
       * given ``owner``'s signed approval.
       *
       * IMPORTANT: The same issues {IERC20-approve} has related to transaction
       * ordering also apply here.
       *
       * Emits an {Approval} event.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       * - `deadline` must be a timestamp in the future.
       * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
       * over the EIP712-formatted function arguments.
       * - the signature must use ``owner``'s current nonce (see {nonces}).
       *
       * For more information on the signature format, see the
       * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
       * section].
       *
       * CAUTION: See Security Considerations above.
       */
      function permit(
          address owner,
          address spender,
          uint256 value,
          uint256 deadline,
          uint8 v,
          bytes32 r,
          bytes32 s
      ) external;
  
      /**
       * @dev Returns the current nonce for `owner`. This value must be
       * included whenever a signature is generated for {permit}.
       *
       * Every successful call to {permit} increases ``owner``'s nonce by one. This
       * prevents a signature from being used multiple times.
       */
      function nonces(address owner) external view returns (uint256);
  
      /**
       * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
       */
      // solhint-disable-next-line func-name-mixedcase
      function DOMAIN_SEPARATOR() external view returns (bytes32);
  }
  
  // File: @openzeppelin/contracts/interfaces/draft-IERC6093.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (interfaces/draft-IERC6093.sol)
  pragma solidity ^0.8.20;
  
  /**
   * @dev Standard ERC20 Errors
   * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC20 tokens.
   */
  interface IERC20Errors {
      /**
       * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
       * @param sender Address whose tokens are being transferred.
       * @param balance Current balance for the interacting account.
       * @param needed Minimum amount required to perform a transfer.
       */
      error ERC20InsufficientBalance(address sender, uint256 balance, uint256 needed);
  
      /**
       * @dev Indicates a failure with the token `sender`. Used in transfers.
       * @param sender Address whose tokens are being transferred.
       */
      error ERC20InvalidSender(address sender);
  
      /**
       * @dev Indicates a failure with the token `receiver`. Used in transfers.
       * @param receiver Address to which tokens are being transferred.
       */
      error ERC20InvalidReceiver(address receiver);
  
      /**
       * @dev Indicates a failure with the `spender`’s `allowance`. Used in transfers.
       * @param spender Address that may be allowed to operate on tokens without being their owner.
       * @param allowance Amount of tokens a `spender` is allowed to operate with.
       * @param needed Minimum amount required to perform a transfer.
       */
      error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed);
  
      /**
       * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
       * @param approver Address initiating an approval operation.
       */
      error ERC20InvalidApprover(address approver);
  
      /**
       * @dev Indicates a failure with the `spender` to be approved. Used in approvals.
       * @param spender Address that may be allowed to operate on tokens without being their owner.
       */
      error ERC20InvalidSpender(address spender);
  }
  
  /**
   * @dev Standard ERC721 Errors
   * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC721 tokens.
   */
  interface IERC721Errors {
      /**
       * @dev Indicates that an address can't be an owner. For example, `address(0)` is a forbidden owner in EIP-20.
       * Used in balance queries.
       * @param owner Address of the current owner of a token.
       */
      error ERC721InvalidOwner(address owner);
  
      /**
       * @dev Indicates a `tokenId` whose `owner` is the zero address.
       * @param tokenId Identifier number of a token.
       */
      error ERC721NonexistentToken(uint256 tokenId);
  
      /**
       * @dev Indicates an error related to the ownership over a particular token. Used in transfers.
       * @param sender Address whose tokens are being transferred.
       * @param tokenId Identifier number of a token.
       * @param owner Address of the current owner of a token.
       */
      error ERC721IncorrectOwner(address sender, uint256 tokenId, address owner);
  
      /**
       * @dev Indicates a failure with the token `sender`. Used in transfers.
       * @param sender Address whose tokens are being transferred.
       */
      error ERC721InvalidSender(address sender);
  
      /**
       * @dev Indicates a failure with the token `receiver`. Used in transfers.
       * @param receiver Address to which tokens are being transferred.
       */
      error ERC721InvalidReceiver(address receiver);
  
      /**
       * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
       * @param operator Address that may be allowed to operate on tokens without being their owner.
       * @param tokenId Identifier number of a token.
       */
      error ERC721InsufficientApproval(address operator, uint256 tokenId);
  
      /**
       * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
       * @param approver Address initiating an approval operation.
       */
      error ERC721InvalidApprover(address approver);
  
      /**
       * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
       * @param operator Address that may be allowed to operate on tokens without being their owner.
       */
      error ERC721InvalidOperator(address operator);
  }
  
  /**
   * @dev Standard ERC1155 Errors
   * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC1155 tokens.
   */
  interface IERC1155Errors {
      /**
       * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
       * @param sender Address whose tokens are being transferred.
       * @param balance Current balance for the interacting account.
       * @param needed Minimum amount required to perform a transfer.
       * @param tokenId Identifier number of a token.
       */
      error ERC1155InsufficientBalance(address sender, uint256 balance, uint256 needed, uint256 tokenId);
  
      /**
       * @dev Indicates a failure with the token `sender`. Used in transfers.
       * @param sender Address whose tokens are being transferred.
       */
      error ERC1155InvalidSender(address sender);
  
      /**
       * @dev Indicates a failure with the token `receiver`. Used in transfers.
       * @param receiver Address to which tokens are being transferred.
       */
      error ERC1155InvalidReceiver(address receiver);
  
      /**
       * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
       * @param operator Address that may be allowed to operate on tokens without being their owner.
       * @param owner Address of the current owner of a token.
       */
      error ERC1155MissingApprovalForAll(address operator, address owner);
  
      /**
       * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
       * @param approver Address initiating an approval operation.
       */
      error ERC1155InvalidApprover(address approver);
  
      /**
       * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
       * @param operator Address that may be allowed to operate on tokens without being their owner.
       */
      error ERC1155InvalidOperator(address operator);
  
      /**
       * @dev Indicates an array length mismatch between ids and values in a safeBatchTransferFrom operation.
       * Used in batch transfers.
       * @param idsLength Length of the array of token identifiers
       * @param valuesLength Length of the array of token amounts
       */
      error ERC1155InvalidArrayLength(uint256 idsLength, uint256 valuesLength);
  }
  
  // File: @openzeppelin/contracts/utils/Context.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)
  
  pragma solidity ^0.8.20;
  
  /**
   * @dev Provides information about the current execution context, including the
   * sender of the transaction and its data. While these are generally available
   * via msg.sender and msg.data, they should not be accessed in such a direct
   * manner, since when dealing with meta-transactions the account sending and
   * paying for execution may not be the actual sender (as far as an application
   * is concerned).
   *
   * This contract is only required for intermediate, library-like contracts.
   */
  abstract contract Context {
      function _msgSender() internal view virtual returns (address) {
          return msg.sender;
      }
  
      function _msgData() internal view virtual returns (bytes calldata) {
          return msg.data;
      }
  
      function _contextSuffixLength() internal view virtual returns (uint256) {
          return 0;
      }
  }
  
  // File: @openzeppelin/contracts/token/ERC20/IERC20.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)
  
  pragma solidity ^0.8.20;
  
  /**
   * @dev Interface of the ERC20 standard as defined in the EIP.
   */
  interface IERC20 {
      /**
       * @dev Emitted when `value` tokens are moved from one account (`from`) to
       * another (`to`).
       *
       * Note that `value` may be zero.
       */
      event Transfer(address indexed from, address indexed to, uint256 value);
  
      /**
       * @dev Emitted when the allowance of a `spender` for an `owner` is set by
       * a call to {approve}. `value` is the new allowance.
       */
      event Approval(address indexed owner, address indexed spender, uint256 value);
  
      /**
       * @dev Returns the value of tokens in existence.
       */
      function totalSupply() external view returns (uint256);
  
      /**
       * @dev Returns the value of tokens owned by `account`.
       */
      function balanceOf(address account) external view returns (uint256);
  
      /**
       * @dev Moves a `value` amount of tokens from the caller's account to `to`.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transfer(address to, uint256 value) external returns (bool);
  
      /**
       * @dev Returns the remaining number of tokens that `spender` will be
       * allowed to spend on behalf of `owner` through {transferFrom}. This is
       * zero by default.
       *
       * This value changes when {approve} or {transferFrom} are called.
       */
      function allowance(address owner, address spender) external view returns (uint256);
  
      /**
       * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
       * caller's tokens.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * IMPORTANT: Beware that changing an allowance with this method brings the risk
       * that someone may use both the old and the new allowance by unfortunate
       * transaction ordering. One possible solution to mitigate this race
       * condition is to first reduce the spender's allowance to 0 and set the
       * desired value afterwards:
       * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
       *
       * Emits an {Approval} event.
       */
      function approve(address spender, uint256 value) external returns (bool);
  
      /**
       * @dev Moves a `value` amount of tokens from `from` to `to` using the
       * allowance mechanism. `value` is then deducted from the caller's
       * allowance.
       *
       * Returns a boolean value indicating whether the operation succeeded.
       *
       * Emits a {Transfer} event.
       */
      function transferFrom(address from, address to, uint256 value) external returns (bool);
  }
  
  // File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/utils/SafeERC20.sol)
  
  pragma solidity ^0.8.20;
  
  
  
  
  /**
   * @title SafeERC20
   * @dev Wrappers around ERC20 operations that throw on failure (when the token
   * contract returns false). Tokens that return no value (and instead revert or
   * throw on failure) are also supported, non-reverting calls are assumed to be
   * successful.
   * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
   * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
   */
  library SafeERC20 {
      using Address for address;
  
      /**
       * @dev An operation with an ERC20 token failed.
       */
      error SafeERC20FailedOperation(address token);
  
      /**
       * @dev Indicates a failed `decreaseAllowance` request.
       */
      error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);
  
      /**
       * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
       * non-reverting calls are assumed to be successful.
       */
      function safeTransfer(IERC20 token, address to, uint256 value) internal {
          _callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
      }
  
      /**
       * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
       * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
       */
      function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
          _callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
      }
  
      /**
       * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
       * non-reverting calls are assumed to be successful.
       */
      function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
          uint256 oldAllowance = token.allowance(address(this), spender);
          forceApprove(token, spender, oldAllowance + value);
      }
  
      /**
       * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
       * value, non-reverting calls are assumed to be successful.
       */
      function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
          unchecked {
              uint256 currentAllowance = token.allowance(address(this), spender);
              if (currentAllowance < requestedDecrease) {
                  revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
              }
              forceApprove(token, spender, currentAllowance - requestedDecrease);
          }
      }
  
      /**
       * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
       * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
       * to be set to zero before setting it to a non-zero value, such as USDT.
       */
      function forceApprove(IERC20 token, address spender, uint256 value) internal {
          bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));
  
          if (!_callOptionalReturnBool(token, approvalCall)) {
              _callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
              _callOptionalReturn(token, approvalCall);
          }
      }
  
      /**
       * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
       * on the return value: the return value is optional (but if data is returned, it must not be false).
       * @param token The token targeted by the call.
       * @param data The call data (encoded using abi.encode or one of its variants).
       */
      function _callOptionalReturn(IERC20 token, bytes memory data) private {
          // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
          // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
          // the target address contains contract code and also asserts for success in the low-level call.
  
          bytes memory returndata = address(token).functionCall(data);
          if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
              revert SafeERC20FailedOperation(address(token));
          }
      }
  
      /**
       * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
       * on the return value: the return value is optional (but if data is returned, it must not be false).
       * @param token The token targeted by the call.
       * @param data The call data (encoded using abi.encode or one of its variants).
       *
       * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
       */
      function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
          // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
          // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
          // and not revert is the subcall reverts.
  
          (bool success, bytes memory returndata) = address(token).call(data);
          return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
      }
  }
  
  // File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Metadata.sol)
  
  pragma solidity ^0.8.20;
  
  
  /**
   * @dev Interface for the optional metadata functions from the ERC20 standard.
   */
  interface IERC20Metadata is IERC20 {
      /**
       * @dev Returns the name of the token.
       */
      function name() external view returns (string memory);
  
      /**
       * @dev Returns the symbol of the token.
       */
      function symbol() external view returns (string memory);
  
      /**
       * @dev Returns the decimals places of the token.
       */
      function decimals() external view returns (uint8);
  }
  
  // File: @openzeppelin/contracts/token/ERC20/ERC20.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/ERC20.sol)
  
  pragma solidity ^0.8.20;
  
  
  
  
  
  /**
   * @dev Implementation of the {IERC20} interface.
   *
   * This implementation is agnostic to the way tokens are created. This means
   * that a supply mechanism has to be added in a derived contract using {_mint}.
   *
   * TIP: For a detailed writeup see our guide
   * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
   * to implement supply mechanisms].
   *
   * The default value of {decimals} is 18. To change this, you should override
   * this function so it returns a different value.
   *
   * We have followed general OpenZeppelin Contracts guidelines: functions revert
   * instead returning `false` on failure. This behavior is nonetheless
   * conventional and does not conflict with the expectations of ERC20
   * applications.
   *
   * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
   * This allows applications to reconstruct the allowance for all accounts just
   * by listening to said events. Other implementations of the EIP may not emit
   * these events, as it isn't required by the specification.
   */
  abstract contract ERC20 is Context, IERC20, IERC20Metadata, IERC20Errors {
      mapping(address account => uint256) private _balances;
  
      mapping(address account => mapping(address spender => uint256)) private _allowances;
  
      uint256 private _totalSupply;
  
      string private _name;
      string private _symbol;
  
      /**
       * @dev Sets the values for {name} and {symbol}.
       *
       * All two of these values are immutable: they can only be set once during
       * construction.
       */
      constructor(string memory name_, string memory symbol_) {
          _name = name_;
          _symbol = symbol_;
      }
  
      /**
       * @dev Returns the name of the token.
       */
      function name() public view virtual returns (string memory) {
          return _name;
      }
  
      /**
       * @dev Returns the symbol of the token, usually a shorter version of the
       * name.
       */
      function symbol() public view virtual returns (string memory) {
          return _symbol;
      }
  
      /**
       * @dev Returns the number of decimals used to get its user representation.
       * For example, if `decimals` equals `2`, a balance of `505` tokens should
       * be displayed to a user as `5.05` (`505 / 10 ** 2`).
       *
       * Tokens usually opt for a value of 18, imitating the relationship between
       * Ether and Wei. This is the default value returned by this function, unless
       * it's overridden.
       *
       * NOTE: This information is only used for _display_ purposes: it in
       * no way affects any of the arithmetic of the contract, including
       * {IERC20-balanceOf} and {IERC20-transfer}.
       */
      function decimals() public view virtual returns (uint8) {
          return 18;
      }
  
      /**
       * @dev See {IERC20-totalSupply}.
       */
      function totalSupply() public view virtual returns (uint256) {
          return _totalSupply;
      }
  
      /**
       * @dev See {IERC20-balanceOf}.
       */
      function balanceOf(address account) public view virtual returns (uint256) {
          return _balances[account];
      }
  
      /**
       * @dev See {IERC20-transfer}.
       *
       * Requirements:
       *
       * - `to` cannot be the zero address.
       * - the caller must have a balance of at least `value`.
       */
      function transfer(address to, uint256 value) public virtual returns (bool) {
          address owner = _msgSender();
          _transfer(owner, to, value);
          return true;
      }
  
      /**
       * @dev See {IERC20-allowance}.
       */
      function allowance(address owner, address spender) public view virtual returns (uint256) {
          return _allowances[owner][spender];
      }
  
      /**
       * @dev See {IERC20-approve}.
       *
       * NOTE: If `value` is the maximum `uint256`, the allowance is not updated on
       * `transferFrom`. This is semantically equivalent to an infinite approval.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       */
      function approve(address spender, uint256 value) public virtual returns (bool) {
          address owner = _msgSender();
          _approve(owner, spender, value);
          return true;
      }
  
      /**
       * @dev See {IERC20-transferFrom}.
       *
       * Emits an {Approval} event indicating the updated allowance. This is not
       * required by the EIP. See the note at the beginning of {ERC20}.
       *
       * NOTE: Does not update the allowance if the current allowance
       * is the maximum `uint256`.
       *
       * Requirements:
       *
       * - `from` and `to` cannot be the zero address.
       * - `from` must have a balance of at least `value`.
       * - the caller must have allowance for ``from``'s tokens of at least
       * `value`.
       */
      function transferFrom(address from, address to, uint256 value) public virtual returns (bool) {
          address spender = _msgSender();
          _spendAllowance(from, spender, value);
          _transfer(from, to, value);
          return true;
      }
  
      /**
       * @dev Moves a `value` amount of tokens from `from` to `to`.
       *
       * This internal function is equivalent to {transfer}, and can be used to
       * e.g. implement automatic token fees, slashing mechanisms, etc.
       *
       * Emits a {Transfer} event.
       *
       * NOTE: This function is not virtual, {_update} should be overridden instead.
       */
      function _transfer(address from, address to, uint256 value) internal {
          if (from == address(0)) {
              revert ERC20InvalidSender(address(0));
          }
          if (to == address(0)) {
              revert ERC20InvalidReceiver(address(0));
          }
          _update(from, to, value);
      }
  
      /**
       * @dev Transfers a `value` amount of tokens from `from` to `to`, or alternatively mints (or burns) if `from`
       * (or `to`) is the zero address. All customizations to transfers, mints, and burns should be done by overriding
       * this function.
       *
       * Emits a {Transfer} event.
       */
      function _update(address from, address to, uint256 value) internal virtual {
          if (from == address(0)) {
              // Overflow check required: The rest of the code assumes that totalSupply never overflows
              _totalSupply += value;
          } else {
              uint256 fromBalance = _balances[from];
              if (fromBalance < value) {
                  revert ERC20InsufficientBalance(from, fromBalance, value);
              }
              unchecked {
                  // Overflow not possible: value <= fromBalance <= totalSupply.
                  _balances[from] = fromBalance - value;
              }
          }
  
          if (to == address(0)) {
              unchecked {
                  // Overflow not possible: value <= totalSupply or value <= fromBalance <= totalSupply.
                  _totalSupply -= value;
              }
          } else {
              unchecked {
                  // Overflow not possible: balance + value is at most totalSupply, which we know fits into a uint256.
                  _balances[to] += value;
              }
          }
  
          emit Transfer(from, to, value);
      }
  
      /**
       * @dev Creates a `value` amount of tokens and assigns them to `account`, by transferring it from address(0).
       * Relies on the `_update` mechanism
       *
       * Emits a {Transfer} event with `from` set to the zero address.
       *
       * NOTE: This function is not virtual, {_update} should be overridden instead.
       */
      function _mint(address account, uint256 value) internal {
          if (account == address(0)) {
              revert ERC20InvalidReceiver(address(0));
          }
          _update(address(0), account, value);
      }
  
      /**
       * @dev Destroys a `value` amount of tokens from `account`, lowering the total supply.
       * Relies on the `_update` mechanism.
       *
       * Emits a {Transfer} event with `to` set to the zero address.
       *
       * NOTE: This function is not virtual, {_update} should be overridden instead
       */
      function _burn(address account, uint256 value) internal {
          if (account == address(0)) {
              revert ERC20InvalidSender(address(0));
          }
          _update(account, address(0), value);
      }
  
      /**
       * @dev Sets `value` as the allowance of `spender` over the `owner` s tokens.
       *
       * This internal function is equivalent to `approve`, and can be used to
       * e.g. set automatic allowances for certain subsystems, etc.
       *
       * Emits an {Approval} event.
       *
       * Requirements:
       *
       * - `owner` cannot be the zero address.
       * - `spender` cannot be the zero address.
       *
       * Overrides to this logic should be done to the variant with an additional `bool emitEvent` argument.
       */
      function _approve(address owner, address spender, uint256 value) internal {
          _approve(owner, spender, value, true);
      }
  
      /**
       * @dev Variant of {_approve} with an optional flag to enable or disable the {Approval} event.
       *
       * By default (when calling {_approve}) the flag is set to true. On the other hand, approval changes made by
       * `_spendAllowance` during the `transferFrom` operation set the flag to false. This saves gas by not emitting any
       * `Approval` event during `transferFrom` operations.
       *
       * Anyone who wishes to continue emitting `Approval` events on the`transferFrom` operation can force the flag to
       * true using the following override:
       * ```
       * function _approve(address owner, address spender, uint256 value, bool) internal virtual override {
       *     super._approve(owner, spender, value, true);
       * }
       * ```
       *
       * Requirements are the same as {_approve}.
       */
      function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual {
          if (owner == address(0)) {
              revert ERC20InvalidApprover(address(0));
          }
          if (spender == address(0)) {
              revert ERC20InvalidSpender(address(0));
          }
          _allowances[owner][spender] = value;
          if (emitEvent) {
              emit Approval(owner, spender, value);
          }
      }
  
      /**
       * @dev Updates `owner` s allowance for `spender` based on spent `value`.
       *
       * Does not update the allowance value in case of infinite allowance.
       * Revert if not enough allowance is available.
       *
       * Does not emit an {Approval} event.
       */
      function _spendAllowance(address owner, address spender, uint256 value) internal virtual {
          uint256 currentAllowance = allowance(owner, spender);
          if (currentAllowance != type(uint256).max) {
              if (currentAllowance < value) {
                  revert ERC20InsufficientAllowance(spender, currentAllowance, value);
              }
              unchecked {
                  _approve(owner, spender, currentAllowance - value, false);
              }
          }
      }
  }
  
  // File: @openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol
  
  
  // OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/ERC20Burnable.sol)
  
  pragma solidity ^0.8.20;
  
  
  
  /**
   * @dev Extension of {ERC20} that allows token holders to destroy both their own
   * tokens and those that they have an allowance for, in a way that can be
   * recognized off-chain (via event analysis).
   */
  abstract contract ERC20Burnable is Context, ERC20 {
      /**
       * @dev Destroys a `value` amount of tokens from the caller.
       *
       * See {ERC20-_burn}.
       */
      function burn(uint256 value) public virtual {
          _burn(_msgSender(), value);
      }
  
      /**
       * @dev Destroys a `value` amount of tokens from `account`, deducting from
       * the caller's allowance.
       *
       * See {ERC20-_burn} and {ERC20-allowance}.
       *
       * Requirements:
       *
       * - the caller must have allowance for ``accounts``'s tokens of at least
       * `value`.
       */
      function burnFrom(address account, uint256 value) public virtual {
          _spendAllowance(account, _msgSender(), value);
          _burn(account, value);
      }
  }
  
  // File: iotube/CrosschainERC20V2.sol
  
  
  pragma solidity >=0.8.0;
  
  
  
  contract CrosschainERC20V2 is ERC20Burnable {
      using SafeERC20 for ERC20;
  
      event MinterSet(address indexed minter);
  
      modifier onlyMinter() {
          require(minter == msg.sender, "not the minter");
          _;
      }
  
      ERC20 public coToken;
      address public minter;
      uint8 private decimals_;
  
      constructor(
          ERC20 _coToken,
          address _minter,
          string memory _name,
          string memory _symbol,
          uint8 _decimals
      ) ERC20(_name, _symbol) {
          coToken = _coToken;
          minter = _minter;
          decimals_  = _decimals;
          emit MinterSet(_minter);
      }
  
      function decimals() public view virtual override returns (uint8) {
          return decimals_;
      }
  
      function transferMintership(address _newMinter) public onlyMinter {
          minter = _newMinter;
          emit MinterSet(_newMinter);
      }
  
      function deposit(uint256 _amount) public {
          depositTo(msg.sender, _amount);
      }
  
      function depositTo(address _to, uint256 _amount) public {
          require(address(coToken) != address(0), "no co-token");
          uint256 originBalance = coToken.balanceOf(address(this));
          coToken.safeTransferFrom(msg.sender, address(this), _amount);
          uint256 newBalance = coToken.balanceOf(address(this));
          require(newBalance > originBalance, "invalid balance");
          _mint(_to, newBalance - originBalance);
      }
  
      function withdraw(uint256 _amount) public {
          withdrawTo(msg.sender, _amount);
      }
  
      function withdrawTo(address _to, uint256 _amount) public {
          require(address(coToken) != address(0), "no co-token");
          require(_amount != 0, "amount is 0");
          _burn(msg.sender, _amount);
          coToken.safeTransfer(_to, _amount);
      }
  
      function mint(address _to, uint256 _amount) public onlyMinter returns (bool) {
          require(_amount != 0, "amount is 0");
          _mint(_to, _amount);
          return true;
      }
  }