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: yrIDSuVuQU, UXTSuVuLcch

A: SuVu
****
Q: QlJnxO, BLJnCQ

A:
Jn
****