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

QgkpBHsrfRYJCa, AdjbKLpBHsrfbpBC
pBHsrf

UCbReSfuLcbzmBCl, snQRReSfuLcbzmjqVPSdpp
ReSfuLcbzm

DALxFZWEvNjIhw, IKfHFZWEvNjIUA

FZWEvNjI