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

Ex Input:
fWJdaAfOCfejXZvidHM, gOpfOCfejXZbtLvSLZI

Ex Output:
fOCfejXZ


Ex Input:
jsXHot, gtXHmB

Ex Output:
XH


Ex Input:
ZZqMnjEHtXzfs, chlODXjEHtXzaHk

Ex Output:

jEHtXz