Liars#220
In a talk show, there are participants who all know each other. Among them, there are always truth-tellers and liars: some participants always tell the truth and others always lie (with at least one truth-teller present). At the end of the program, the host decides to determine to which group each participant belongs. To do this, the host asks everyone the following question: "How many among you always tell the truth?" Each participant responds with a number between and . After collecting these responses, the host may select certain participants and ask them the same question again, but this time each selected participant answers only about the selected group. Based on the answers, the host can definitively identify who is a truth-teller and who is a liar.
Write a program that, given the number of participants and their answers to the first question, determines the minimum number of participants the host needs to select for repeated questioning so that everyone can be reliably identified. If it is already possible to uniquely determine the truth-tellers and liars after the first round, output .
The first line contains a single integer (1 \leq N \leq 1000) — the number of participants. The second line contains integers from to — the answers of each participant to the first question.
Output a single integer — the minimum number of participants the host needs to select for repeated questioning. If it is possible to uniquely determine the truth-tellers and liars after the first round, output .
Example 1