instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
skZGHS, HsZGge
answer:
ZG


question:
lOedgdw, aoedgpn
answer:
edg


question:
DDBWTQDLUAIfFolD, MtaLUAIfFobamLHQj
answer:

LUAIfFo