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

Ex Input:
NmtypJ, tQtyZD

Ex Output:
ty


Ex Input:
bSBuJiZniSlZtO, AcuJiZniSRAOAv

Ex Output:
uJiZniS


Ex Input:
UjZzHrWZU, wEnzHrWUSK

Ex Output:

zHrW