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

Input: Consider Input: zBxuZfJgYrlRSzkmAktO, YNMgYrlRSzklmBOH

Output: gYrlRSzk


Input: Consider Input: HXYkGv, GCYksu

Output: Yk


Input: Consider Input: oEZyFB, oCZysq


Output: Zy