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

Input: Consider Input: hRVyvwHqnN, geHeyvwHqiBiYJ

Output: yvwHq

Input: Consider Input: BdqUloJanutXoOyfLsuA, NRDloJanutXoOQY

Output: loJanutXoO

Input: Consider Input: VGzaIXCnl, ZDetzaIXCXnf
Output: zaIXC