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

Q: kOrQWjLKnwN, xFsWjLKgr

A: WjLK
****
Q: UtUSmsOI, dCUSmGoQ

A: USm
****
Q: xFFJRPVxG, NErJRPRiq

A:
JRP
****