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: YWNPkA, LuNPnN

Answer: NP


Question: zzEhnt, sYEhtc

Answer: Eh


Question: wUWwrctcyxRkEOkkuhEywdiRHy, ZnNQeqxRkEOkkuhECWBWqmzgD

Answer:
xRkEOkkuhE


