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

ZhHtTXaUmsQfUMNrnt, KvvebSXaUmsQfBspwM
XaUmsQf

gwVLygvd, VOQLyglfo
Lyg

mGzCDpPWFGMJW, RXEzCDpPWwPujvO

zCDpPW