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

Q: FQAznAuFjoBKRKB, hPmtFFPnuAznAuFjoBKTgkeJyjcd

A: AznAuFjoBK
****
Q: STvKOHq, XMGvKOdyM

A: vKO
****
Q: LJJvLTK, jpFJvLqh

A:
JvL
****