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: YCAyruPTTHWhCYaiXfIl, OETdzqAyruPTTHWgS

A: AyruPTTHW
****
Q: CVbSrDKeqeOS, VAqrDKenTuS

A:
rDKe
****