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

Q: mOGzbnDXWnNurkBXtcqZ, NLahGzbnDXWnNYgMTOR

A: GzbnDXWnN
****
Q: DUhUbmfLuOFAQann, kwnzfLuOFAErR

A: fLuOFA
****
Q: wvROIZTpNZ, dBHROIZqrJr

A:
ROIZ
****