instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
UQDJDbzqDxsMzUL, BxClJDbzqDxLxlngc
answer:
JDbzqDx


question:
RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML
answer:
chtNymcsw


question:
WkGzndDGhCGF, WsMNndDGhBpmJ
answer:

ndDGh