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

Ex Input:
SIIPePlrkftKkzfgdjg, JqNnXHrkftKkzOMUwmc

Ex Output:
rkftKkz


Ex Input:
IVnbnqBqdPcXfHotUzCYoaGQy, PAlyypBRRBqdPcXfHotpZs

Ex Output:
BqdPcXfHot


Ex Input:
RDxdOJPXOwSjCY, zKGzEQJPXOwSvnP

Ex Output:

JPXOwS


