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

Q: KKrCLvJKRoyV, WDeLvJKCBdS

A: LvJK
****
Q: lQwpMQRxuVbJDv, UkzwpMQRxuDVT

A: wpMQRxu
****
Q: AaScaXsVYSYAOn, ZzlgaXsVYbd

A:
aXsVY
****