instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
HaLZdTX, tLLZdEXN
answer:
LZd


question:
DFRoMPNDAzNgtLsEPseOzC, qykyPjDAzNgtLsEPYTsNrJaNK
answer:
DAzNgtLsEP


question:
FtcgeV, cecgmK
answer:

cg