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

Ex Input:
kOrQWjLKnwN, xFsWjLKgr

Ex Output:
WjLK


Ex Input:
CUlMsvov, iflMsSRp

Ex Output:
lMs


Ex Input:
JJOpVjYK, rwhOpVjQSiO

Ex Output:

OpVj