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

Q: jsXHot, gtXHmB

A: XH
****
Q: JAfPtjqqUYMD, cpXItjqqFN

A: tjqq
****
Q: bPPOYlQWuYSQuZbsAM, ucWuYSQuZbUqw

A:
WuYSQuZb
****