In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

Q: ChKUlYUTQQBjZMZkgEed, lmQQBjZMZkgdEf

A: QQBjZMZkg
****
Q: WlqGjLNrxXeUrKCZel, pDSsmNrxXeUrKCslBXBbRu

A: NrxXeUrKC
****
Q: KMMhcl, hOMhwN

A:
Mh
****