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

iYSNsY, HSSNhP
SN

lLxXqKscqizXTO, TqrKscqizutDudo
Kscqiz

sUdaWtsiRgqAYHykrHwjyDvZgD, MJdFXYiRgqAYHykrakSGHMr

iRgqAYHykr