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:
jinzsW, SMnzaW

Ex Output:
nz


Ex Input:
YznsTprDgQCjk, qLprDgQhluI

Ex Output:

prDgQ