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

[EX Q]: FSwxBJ, iTwxAa
[EX A]: wx

[EX Q]: OVVkkdeHoFlyNROyCP, zFVUJbvkkdeHoFlysF
[EX A]: kkdeHoFly

[EX Q]: hHmTsWzqreHPEYGZyXrhkNj, mLreHPEYGZySqWBsSzx
[EX A]:
reHPEYGZy