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: XeQwOS, OuQwNR

Output: Qw


Input: Consider Input: LZxGqyQQLJwYQw, fVHtyQQLJKqd


Output: yQQLJ