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

Ex Input:
sdGIVJPsWWszKPCGk, ghRJPsWWszKcJUg

Ex Output:
JPsWWszK


Ex Input:
hRVyvwHqnN, geHeyvwHqiBiYJ

Ex Output:
yvwHq


Ex Input:
lfELWaFtUWyPgCUOObFvWmySBGHTv, hqsXkyPgCUOObFvCHJIwZaX

Ex Output:

yPgCUOObFv