instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
nxTtNYaazlOyEBApiUSJS, BLazlOyEBCV
answer:
azlOyEB


question:
lLxXqKscqizXTO, TqrKscqizutDudo
answer:
Kscqiz


question:
RAYOAI, mgYOpT
answer:

YO