instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx
answer:
QXEFSgRZ


question:
iYSNsY, HSSNhP
answer:
SN


question:
OANglKwDXxzMUoPjvfggxyBMnN, glPDkiYMAuzMUoPjvfggmMzBtn
answer:

zMUoPjvfgg


