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

[EX Q]: pBDnbfrAxJfVhPBxheXZGp, LMtorAxJfVhPnnaed
[EX A]: rAxJfVhP

[EX Q]: spGRUmIYuGl, qkqRUmItqU
[EX A]: RUmI

[EX Q]: ymuRNc, bduRSM
[EX A]:
uR