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: PGjDRPDzGaBR, rpIJRPDzWi

Answer: RPDz


Question: PQSFjlnU, kTSFjMUh

Answer: SFj


Question: mUsBPb, trsBen

Answer:
sB