package yukicoder;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Main {
	public static void main(String[] args) {
		BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
		try {

			int N = Integer.parseInt(read.readLine());
			String[] line = read.readLine().split(" ");
			List<Integer> list = new ArrayList<>(N);

			list.add(0);
			for (int i = 0; i < N; ++i) {
				list.add(Integer.parseInt(line[i]));
			}
			list.add(Integer.MAX_VALUE);
			list.sort(null);

			int ans = 0;
			for (int i = 1; i <= N; ++i) {
				if (list.get(i - 1).intValue() != list.get(i).intValue() && list.get(i + 1).intValue() != list.get(i).intValue()) {
					++ans;
				}
			}

			System.out.println(ans);

		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}