CF23B Party

$ n $ people came to a party. Then those, who had no friends among people at the party, left. Then those, who had exactly 1 friend among those who stayed, left as well. Then those, who had exactly $ 2,3,...,n-1 $ friends among those who stayed by the moment of their leaving, did the same. What is the maximum amount of people that could stay at the party in the end?

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