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

[EX Q]: EOacPYivmmUlYenynBqAwx, MoZWMOeXmUlYenynBEendWg
[EX A]: mUlYenynB

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

[EX Q]: HNLwMcnctpboywoZg, WtrjctpboywoFvQ
[EX A]:
ctpboywo