import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int[] A = new int[N];
        for (int i = 0; i < N; i++) {
            A[i] = scanner.nextInt();
        }


        Arrays.sort(A);
        int count = 0;
        if (N > 1) {
            if (A[0] != A[1]) {
                count++;
            }
        }
        if (N > 2) {
            if (A[N - 2] != A[N - 1]) {
                count++;
            }
        }

        for (int i = 1; i < N - 1; i++) {
            if (A[i - 1] != A[i] && A[i] != A[i + 1]) {
                count++;
            }
        }

        System.out.println(count);
    }

}