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

RwduMBkDazrwZP, UPzcwtWMBkDazrAw
MBkDazr

ZhHtTXaUmsQfUMNrnt, KvvebSXaUmsQfBspwM
XaUmsQf

NfzJOtrNdOY, OociuJOtrNnTd

JOtrN