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

Input: Consider Input: DwkTGsIXLfmjMV, VqRlMxtsSBkTGsIXLfmjbvI

Output: kTGsIXLfmj


Input: Consider Input: mCxQTIaXN, mWQTIaxzPT

Output: QTIa


Input: Consider Input: GcaDvtZdyu, upWSvtZdRf


Output: vtZd