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: tyVlHfTPLRSdFilXnSfqQ, bkTPLRSdFiMgXC
Example Output: TPLRSdFi

Example Input: iqDzFQkpRQtmJ, UejzFQkpsXQhS
Example Output:
zFQkp

