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

CiElmOvTqJGVJkfSaDRzE, EjDJwMyxTvTqJGVJkfluB
vTqJGVJkf

egYXVtCPvWxP, VMOolyVtCPvWjIx
VtCPvW

yKMjwyPZfSZfIIEzTnwkmX, hEpHQfSZfIIEzJuduBvbH

fSZfIIEz