pragma solidity ^0.4.24;

contract OverflowAndUnderflow{
   
   function overflow() public pure returns(uint256){
       uint256 max = 2**256-1;
       return max + 1;
   }
   
   function underflow() public pure returns(uint256){
       uint256 min = 0;
       return min - 1;
   }
   
}