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

Q: PGjDRPDzGaBR, rpIJRPDzWi

A: RPDz
****
Q: iYSNsY, HSSNhP

A: SN
****
Q: YYoWaJBHcgdWEmCZmpqBUPBz, QjTHHFvuwHcgdWEmCZmshslYDk

A:
HcgdWEmCZm
****