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: VByrCcgcxCfPGDFqIWGloQZTMQf, OqfPGDFqIWGlalTCCkKkMf

Answer: fPGDFqIWGl


Question: QqtCFzXHPNFXx, XECFzXHPSGwUuk

Answer: CFzXHP


Question: LzrckivOlzx, UeybkivOxnw

Answer:
kivO