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

Q: FiKGCRXutEOzMqP, xdxRXutEsl

A: RXutE
****
Q: OVZxWYzAAxG, rStOxWYzJeoC

A: xWYz
****
Q: FlJJxjLcTT, lZOJJxjcI

A:
JJxj
****