instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
kUoqCMPFTqGE, guoqCMPkwJs
answer:
oqCMP


question:
CzkPtkpMTDeNZwCPbJJn, HzpMVDeNZwCPbJVOU
answer:
DeNZwCPbJ


question:
NRKwexltsMtsuDk, htJlexltsMRsHA
answer:

exltsM