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

Ex Input:
oCtWZYdkvZ, pkktWZYdEHMW

Ex Output:
tWZYd


Ex Input:
JXnHYuZvAYK, zhUYuZvASGhd

Ex Output:
YuZvA


Ex Input:
HHYbGxprMmpZS, TRxprMmXcoAA

Ex Output:

xprMm