instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
ChKUlYUTQQBjZMZkgEed, lmQQBjZMZkgdEf
answer:
QQBjZMZkg


question:
PShMbsbexXGlpBuMMDZZS, sVqGxSexXGlpBxuHXoI
answer:
exXGlpB


question:
nVYOTRAdVlmaxWHoZAVwefRNj, KICXrYodVlmaxWHokruYAn
answer:

dVlmaxWHo