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

DGvUCrUVlUnQBShkWnfnceGasvI, NfzGUnQBShkWnpLMnY
UnQBShkWn

skZGHS, HsZGge
ZG

KXnUolVbgoAFfs, OIUolVbgoAogYpTibU

UolVbgoA