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

Q: ykDpbd, YFDpmO

A: Dp
****
Q: ZhHtTXaUmsQfUMNrnt, KvvebSXaUmsQfBspwM

A: XaUmsQf
****
Q: XqyPjqNZDEK, EfwPjqNgjIP

A:
PjqN
****