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

KfjqnJLciTXqkJK, yqfRcfqnJLcisSB
qnJLci

YCAyruPTTHWhCYaiXfIl, OETdzqAyruPTTHWgS
AyruPTTHW

ZhqrtUcJYLWmKZHFOhWFJRFrt, hSHcJYLWmKZHFouvcP

cJYLWmKZHF