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

Q: uqazNuZhdJhw, KbnrzNuZhBdp

A: zNuZh
****
Q: RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML

A: chtNymcsw
****
Q: PUWzPlIae, PFnWWzPlIWCsTf

A:
WzPlI
****