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

HKCoXQsLRtowYJ, PGRzNUQsLRtoLcqkn
QsLRto

NwmTIZSnlKGG, qAYIZSnfWRd
IZSn

aNTbdaEYuuhcrhi, SOOaEYuuhQhJNh

aEYuuh