instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
hRVyvwHqnN, geHeyvwHqiBiYJ
answer:
yvwHq


question:
OgWFOfjNYmXVjBBvOdunIc, eGljKGnzFKFOfjNYmXVjdlqsT
answer:
FOfjNYmXVj


question:
JbzlNphmesiOyb, lxRqZUNjlNphmesitM
answer:

lNphmesi