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

xeKSiBafhOWBbYwlGaQ, GUfIsKgafhOWBbYiFWnptAt
afhOWBbY

lLxXqKscqizXTO, TqrKscqizutDudo
Kscqiz

gnhXIgIqgzVi, YITIgIqkEZ

IgIq