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

Ex Input:
yiKkIxbKvNk, znaIxbKggg

Ex Output:
IxbK


Ex Input:
bSBuJiZniSlZtO, AcuJiZniSRAOAv

Ex Output:
uJiZniS


Ex Input:
ErIXMwhn, oaLIXMwID

Ex Output:

IXMw