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

[EX Q]: ATmVEtUuZOgsBUuL, UMUuZOgsBPVT
[EX A]: UuZOgsB

[EX Q]: MriFNpGM, yaiFNduk
[EX A]: iFN

[EX Q]: zeaIwmHnNyQy, uYDazkIwmHnNtws
[EX A]:
IwmHnN