import java.util.*;
public class New {
	public static void main(String[] arg){
		Scanner sc = new Scanner(System.in);
		int n,count=0;
		n = sc.nextInt();
		int[] a = new int[n];
		for(int i = 0; i< n;i++){
			a[i] = sc.nextInt();
		}
		Arrays.sort(a);
		if(a[0] != a[1])count++;
		for(int i = 0;i<n-2;i++){
			if(a[i] != a[i+1] && a[i+1] != a[i+2])count++;
		}
		if(a[n-2] != a[n-1])count++;
		System.out.println(count);
	}
}