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

Ex Input:
OezHeoe, ouUzHemU

Ex Output:
zHe


Ex Input:
UtUSmsOI, dCUSmGoQ

Ex Output:
USm


Ex Input:
eSfbrVhawOlhTxnjD, EJbrVhawOFW

Ex Output:

brVhawO