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

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

[EX Q]: lLxXqKscqizXTO, TqrKscqizutDudo
[EX A]: Kscqiz

[EX Q]: zQzcYkxaomirOMqHIkezf, KPihthnhJccYkxaomirOkRDMsEFOcs
[EX A]:
cYkxaomirO