//Write your own contracts here. Currently compiles using solc v0.4.15+commit.bbb8e64f. pragma solidity ^0.4.18; contract SimpleStore { uint _a = 1; uint max = 0xff; uint256 offset; uint256 position; mapping(uint256 => uint256) listings; function add() public { offset = _a / 256; position = _a & 0xff; listings[offset] |= (1 << position); _a++; } function a() external view returns (uint) {return _a;} function o() external view returns (uint) {return offset;} function p() external view returns (uint) {return position;} function l() external view returns (uint) {return listings[offset];} } 0.4.18