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

[EX Q]: eNuawupVqQ, RIawuplUIf
[EX A]: awup

[EX Q]: LJJvLTK, jpFJvLqh
[EX A]: JvL

[EX Q]: UtUSmsOI, dCUSmGoQ
[EX A]:
USm