import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int [] A = new int [N+2];
        A[0] = 0;
        A[N+1] = Integer.MAX_VALUE;
        for(int i=1; i<=N; i++){
            A[i] = sc.nextInt();
        }
        Arrays.sort(A);
        int count = 0;
        for(int i=1; i<=N; i++){
            if(A[i]!=A[i-1] && A[i]!=A[i+1]){
                count++;
            }
        }
        System.out.println(count);
    }
}