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

[EX Q]: PGjDRPDzGaBR, rpIJRPDzWi
[EX A]: RPDz

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

[EX Q]: EpaSEYArlAkfRZBEQIAp, sGpCSEYArlAkfRyYzwwYT
[EX A]:
SEYArlAkfR