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

[EX Q]: RAmKlEAUfWcgF, ZlWfEAUfWvVRa
[EX A]: EAUfW

[EX Q]: rvLoiycpZw, idcvoiycpcLyD
[EX A]: oiycp

[EX Q]: rkfWtOBAtrW, BiOuWtOBAAiAH
[EX A]:
WtOBA