instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
TUAHhdvHIBxogI, LjfGsAHhdvHJcSdNV
answer:
AHhdvH


question:
HSsyZzZLZAAq, MFEZzZLJC
answer:
ZzZL


question:
tvEMoYVqNRStS, WYJNhYVqNRfeB
answer:

YVqNR