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: vytthSjj, XVttthSFAvk

Answer: tthS


Question: DQBpdnwVDcnCDEWpD, gAtCdnwVDcnCYv

Answer: dnwVDcnC


Question: ZotCQacKk, hdgCQafi

Answer:
CQa