instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
pBDnbfrAxJfVhPBxheXZGp, LMtorAxJfVhPnnaed
answer:
rAxJfVhP


question:
cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx
answer:
QXEFSgRZ


question:
bxCxQSywEzOSnYvAZC, PhywEzOSiJiFz
answer:

ywEzOS