instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
CdRbREFMEDTXnEzgn, zHLEMMEDTXnEPH
answer:
MEDTXnE


question:
esIMEOgV, tNIMEybb
answer:
IME


question:
MZhzeUvI, ieQhzeFQ
answer:

hze