sum+simple

pragma solidity ^0.4.20;

contract sum{

    uint balance;

    function update (uint amount) public returns (identity, uint){

        balance+=amount;

        return (msg.sender, balance);

    }

    function get() public view returns (uint) {

        return balance;

    }

}

pragma solidity >=0.4.0 <0.7.0;

contract SimpleStorage {

uint storedData;

function set(uint x) public {

  storedData = x;

}

function get() public view returns (uint) {

  return storedData;

}

}