instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML
answer:
chtNymcsw


question:
RyaNyUvXAaZHLXUtYuz, CkbsWxZyUvXAaZHLXJJzugDy
answer:
yUvXAaZHLX


question:
OhMVLbQhBxEaOZY, iDVLbQhBxBiiD
answer:

VLbQhBx