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

Example Input: VeLJEBYpZwxVQlo, EZEBYpZwxVQIxjFj
Example Output: EBYpZwxVQ

Example Input: pySBCdpe, AEBCdOR
Example Output: BCd

Example Input: PQCjJwXurLeN, vsjJwXuOy
Example Output:
jJwXu