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

Ex Input:
gwVLygvd, VOQLyglfo

Ex Output:
Lyg


Ex Input:
KKrCLvJKRoyV, WDeLvJKCBdS

Ex Output:
LvJK


Ex Input:
jkhSWYieckVbIMyWQJ, CnWhSWYieckVbaVy

Ex Output:

hSWYieckVb