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: ARGchkRez, kUwchkZPE

Answer: chk


Question: QvtDqzQiSknPbRCG, hVxHdqzQiSknPbumdpNIf

Answer: qzQiSknPb


Question: IueMmcHDRoSorDsXZ, EpHDRoSoCJQUtV

Answer:
HDRoSo