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

Ex Input:
dxqZUOvRprXyFfjQfTWBhR, biSVjOvRprXyFfDtuFWQ

Ex Output:
OvRprXyFf


Ex Input:
QaxEaxdouNyyvNAn, wRjWSaxdouNyyrriQiG

Ex Output:
axdouNyy


Ex Input:
nRVMfAlXpWj, jkfAlXater

Ex Output:

fAlX