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

Ex Input:
nrIHKzJCdAQzUDRBYpg, JDzJCdAQzUMMYrLcfO

Ex Output:
zJCdAQzU


Ex Input:
ztkWLUJQXxP, fYluOkWLUJKDX

Ex Output:
kWLUJ


Ex Input:
CaUdUGkSBphgR, IyRTyzUyUdUGkSBplYzFCH

Ex Output:

UdUGkSBp