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

Input: Consider Input: rqhQxQQDdYwemFiiwcfVx, cEQDdYwemFtwpfNJC

Output: QDdYwemF

Input: Consider Input: EOacPYivmmUlYenynBqAwx, MoZWMOeXmUlYenynBEendWg

Output: mUlYenynB

Input: Consider Input: hDoRvNbbwG, EfxdXvoRvNbbCrhvD
Output: oRvNbb