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

[EX Q]: OrcQOvMBhmwP, mnWrzcQOvMBnLwI
[EX A]: cQOvMB

[EX Q]: pIkAtJHVcvzzZVz, btWerNSHVcvzzZTz
[EX A]: HVcvzzZ

[EX Q]: aUwJTTWZsqXJs, rHrHGTTWZsqonYypx
[EX A]:
TTWZsq