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

Ex Input:
eJPZzg, lFPZbI

Ex Output:
PZ


Ex Input:
qQkmYsYN, UhkmYHSy

Ex Output:
kmY


Ex Input:
NsIdQEvPL, eRnuIdQEMnbW

Ex Output:

IdQE