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

Ex Input:
ZhHtTXaUmsQfUMNrnt, KvvebSXaUmsQfBspwM

Ex Output:
XaUmsQf


Ex Input:
BmwpAnWJ, klVwpAFw

Ex Output:
wpA


Ex Input:
iVzzNbwddqMbs, iSzxBnNbwddqMWmDSDD

Ex Output:

NbwddqM