interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

   
    function allowance(address owner, address spender) external view returns (uint256);

   
    function approve(address spender, uint256 amount) external returns (bool);

  
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

  
    event Transfer(address indexed from, address indexed to, uint256 value);

  
    event Approval(address indexed owner, address indexed spender, uint256 value);
}
function balanceOf(address account) external view returns (uint256);

/**
 * @dev Returns the amount of tokens owned by `account`.
 */