interface IERC20 {
    //저는 7년 동안 한국에서 살았어요 
    //한국어능력시험
    //대한민국
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    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 totalSupply() external view returns (uint256);

//저는 7년 동안 한국에서 살았어요 
//한국어능력시험
//대한민국