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

Ex Input:
yITbYie, TlqTbYomH

Ex Output:
TbY


Ex Input:
SFQHJlK, dHfQHJoUC

Ex Output:
QHJ


Ex Input:
CMfAXqgUjCmy, JQfZXqgUgr

Ex Output:

XqgU