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: CUxfOt, dyxfNp

Answer: xf


Question: lrBJDRkT, jmBJDrI

Answer: BJD


Question: BlxFvrDuqYnavVD, EQgcMvrDuqYRx

Answer:
vrDuqY