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

Ex Input:
hRVyvwHqnN, geHeyvwHqiBiYJ

Ex Output:
yvwHq


Ex Input:
OezHeoe, ouUzHemU

Ex Output:
zHe


Ex Input:
wnESdmuQ, QlESdmXP

Ex Output:

ESdm