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

Ex Input:
CwTYJWQbzEZkvcqKn, hBnhJWQbzEZkKmVM

Ex Output:
JWQbzEZk


Ex Input:
iYSNsY, HSSNhP

Ex Output:
SN


Ex Input:
MXKrdjvfx, dlurdjKt

Ex Output:

rdj