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

Ex Input:
xfZYYDKEqoRRu, ztCeYYDKEqoPG

Ex Output:
YYDKEqo


Ex Input:
Owbiay, exbime

Ex Output:
bi


Ex Input:
WoWcxoxkWgIerR, QytOuaWcxoxkWgIYuIbl

Ex Output:

WcxoxkWgI