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

Q: SODsrWUjUBSgA, WIWUjUBCUUs

A: WUjUB
****
Q: HhBhJMpxpty, MxTJMpxnQEf

A: JMpx
****
Q: NoPkwvQqO, YgkwvLX

A:
kwv
****