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

Q: VGRjWGHRcBdFmkVg, eSwqALQXWGHRcBdFsDXCM

A: WGHRcBdF
****
Q: spGRUmIYuGl, qkqRUmItqU

A: RUmI
****
Q: PxMdJfofqZzOVpqsn, EqkoGKqLMdJfofqZYvEDNLS

A:
MdJfofqZ
****
