In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
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Question: QqtCFzXHPNFXx, XECFzXHPSGwUuk

Answer: CFzXHP


Question: fdinRdwwlntwqzYGhV, ZefonRdwwlntoWQbh

Answer: nRdwwlnt


Question: IKMizzIudFW, HZyCAZizzIudIm

Answer:
izzIud