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

Ex Input:
QlJnxO, BLJnCQ

Ex Output:
Jn


Ex Input:
xQcYRVFFqrVAMsBm, VErcKZvcYRVFFqzKo

Ex Output:
cYRVFFq


Ex Input:
hjiCDnSgQpWLItD, FRbnSgQpElCV

Ex Output:

nSgQp