instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
njzfcapS, JDzfcYQh
answer:
zfc


question:
oZZUNCUHtIiauDxQ, OdindZUNCUHtIiLQmWJJf
answer:
ZUNCUHtIi


question:
JaMbQPkMCFzsYABXSMww, OGBbMbQPkMCFzFxoiMRbC
answer:

MbQPkMCFz