How can I change Scrypt to SHA256 hash?

[Many Coins]

Hello!

That is the function on generate genesis-hash for Litecoin:

Code:

if (true && block.GetHash() != hashGenesisBlock)
        {
            printf("Searching for genesis block...\n");
            // This will figure out a valid hash and Nonce if you're
            // creating a different genesis block:
            uint256 hashTarget = CBigNum().SetCompact(block.nBits).getuint256();
            uint256 thash;
            char scratchpad[SCRYPT_SCRATCHPAD_SIZE];

            loop
            {
                scrypt_1024_1_1_256_sp(BEGIN(block.nVersion), BEGIN(thash), scratchpad);
                if (thash <= hashTarget)
                    break;
                if ((block.nNonce & 0xFFF) == 0)
                {
                    printf("nonce %08X: hash = %s (target = %s)\n", block.nNonce, thash.ToString().c_str(), hashTarget.ToString().c_str());
                }
                ++block.nNonce;
                if (block.nNonce == 0)
                {
                    printf("NONCE WRAPPED, incrementing time\n");
                    ++block.nTime;
                }
            }
            printf("block.nTime = %u \n", block.nTime);
            printf("block.nNonce = %u \n", block.nNonce);
            printf("block.GetHash = %s\n", block.GetHash().ToString().c_str());
            
            }

And it is working.

How can I change this, to generate genesis-hash for Bitcoin?

I understand that I need to change 1-2 lines, but I do not understand how

Thank you!