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

[Q]: XWKEpwGRkfCFZGOyZQOoypx, lhQkmVqeRkfCFZGOyugPLqs
[A]: RkfCFZGOy


[Q]: nxTtNYaazlOyEBApiUSJS, BLazlOyEBCV
[A]: azlOyEB


[Q]: ztkWLUJQXxP, fYluOkWLUJKDX
[A]:
kWLUJ