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

Input: Consider Input: RMurrwPjlfG, QBKrrwPDkTM

Output: rrwP


Input: Consider Input: wYhGWdRC, cFGWdHEy

Output: GWd


Input: Consider Input: bDTLkzJriKR, VzdLkzJrGO


Output: LkzJr