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

[EX Q]: gHFwDorPbNPORVgdLW, AfqDQvCGFwDorPbNPVPVmbQ
[EX A]: FwDorPbNP

[EX Q]: JKZiYILNeNQbJyznES, PHKILNeNQbJylltYH
[EX A]: ILNeNQbJy

[EX Q]: HZGkQifaDQKgZfGyBC, YHYrdZfaDQKgfUh
[EX A]:
faDQKg