+ uint256 balanceBefore = IERC721(nftContract).balanceOf(msg.sender);
207:     firstTokenId = INFTDropCollectionMint(nftContract).mintCountTo(count, msg.sender);
+ uint256 balanceAfter = IERC721(nftContract).balanceOf(msg.sender);
+ require(balanceAfter == balanceBefore + count, "minting failed")
