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

Ex Input:
uGDJixAmSiVaFRmfKRM, NsTGxsJixAmSiVageSw

Ex Output:
JixAmSiVa


Ex Input:
vJtmxQmHEq, yobgAtmxQmMeoLz

Ex Output:
tmxQm


Ex Input:
xQcYRVFFqrVAMsBm, VErcKZvcYRVFFqzKo

Ex Output:

cYRVFFq