interface ERC20{
    //function approve(address spender, uint256 value)external returns(bool);
    //function allowance(address _owner, address _spender) external view returns (uint256 remaining);
    function balanceOf(address _owner) external view returns (uint256 balance);
    function transfer(address _to, uint256 _value) external returns (bool success);
}
function balanceOf(address _owner) external view returns (uint256 balance);

//function approve(address spender, uint256 value)external returns(bool);
//function allowance(address _owner, address _spender) external view returns (uint256 remaining);