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

Ex Input:
ztkWLUJQXxP, fYluOkWLUJKDX

Ex Output:
kWLUJ


Ex Input:
oWwqraAz, uxTqraonu

Ex Output:
qra


Ex Input:
jcACCf, gPACQr

Ex Output:

AC