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

Q: RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML

A: chtNymcsw
****
Q: uHGHiARtdJbuG, OdZmiARtdrhC

A: iARtd
****
Q: kWproSeMzNmpGko, fQSeMzNMbB

A:
SeMzN
****