diff --git a/CCTF_Solutions_main/ctf.sol b/CCTF_Solutions_main/ctf.sol
index da30050..7c0246d 100644
--- a/CCTF_Solutions_main/ctf.sol
+++ b/CCTF_Solutions_main/ctf.sol
@@ -13,7 +13,6 @@ contract CCTF9 is Verifier{
     address public admin;
     uint256 public volStart;
     uint256 public volMaxPoints;
-    uint256 public powDiff;
     bool public started;
 
     enum PlayerStatus {
@@ -56,10 +55,9 @@ contract CCTF9 is Verifier{
     event FlagRemoved(uint256 indexed flagId);
     event FlagSolved(uint256 indexed flagId, address indexed solver);
 
-    constructor(uint256 _volMaxPoints, uint256 _powDiff) {
+    constructor(uint256 _volMaxPoints) {
         admin = msg.sender;
         volMaxPoints = _volMaxPoints;
-        powDiff = _powDiff;
         started = false;
     }
 
@@ -77,15 +75,9 @@ contract CCTF9 is Verifier{
         emit FlagAdded(_flagId, _flagHash);
     }
 
-    function setPowDiff(uint256 _powDiff) external onlyAdmin {
-        powDiff = _powDiff;
-    }
-
 
     function register(string memory _RTFM) external {
         require(players[msg.sender].status == PlayerStatus.Unverified, 'Already registered or banned');
-        //uint256 pow = uint256(keccak256(abi.encodePacked("CCTF", msg.sender,"registration", nonce)));
-        //require(pow < powDiff, "invalid pow");
         require(keccak256(abi.encodePacked('I_read_it')) == keccak256(abi.encodePacked(_RTFM)));  // PoW can be used for harder challenges, this is Entry!
         players[msg.sender].status = PlayerStatus.Verified;
     }
@@ -112,7 +104,7 @@ contract CCTF9 is Verifier{
             inputs[8+i] = addr[i];
         }
         bool valid = verifyTx(p,inputs);
-        assert(valid);
+        require(valid, "Your proof is invalid");
 
 
         Solves[msg.sender][_submitFor] = true;
@@ -128,7 +120,7 @@ contract CCTF9 is Verifier{
     }
 
 
-    function addressToUint32 (address _addr) public view returns (uint32[5] memory)
+    function addressToUint32 (address _addr) public pure returns (uint32[5] memory)
     {
         uint256 targetUint = uint256(uint160(_addr));
         uint32[5] memory addr = [uint32(targetUint/4294967296**4),uint32(targetUint/4294967296**3),uint32(targetUint/4294967296**2),uint32(targetUint/4294967296),uint32(targetUint)];