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

BeEgLISxThm, UGLISxEtP
LISx

GFhJafTV, waHhJaji
hJa

vUFFzcHATeKlydFrGvjWvNKvvc, yFAEbDTTATeKlydFrGolIZQVpO

ATeKlydFrG