interface IERC20 {
    /**
        * @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);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

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