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

Ex Input:
mXHhaCEIwqwEZcz, JZPXbYHhaCEIwZmna

Ex Output:
HhaCEIw


Ex Input:
IKrQfT, crrQRg

Ex Output:
rQ


Ex Input:
KjkYcCaWSRQhLwQxy, OFQbYcCaWSRfPl

Ex Output:

YcCaWSR