import java.util.*;
public class Novelty2{
	public static void main(String... args){
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		System.out.println(counter(n,scan));
	}
	public static int counter(int n,Scanner scan){
		int[] list = new int[n];
		for(int i = 0; i < n; i++){
			list[i] = scan.nextInt();
		}
		Arrays.sort(list);
		int count=0;
		int c=0;
		for(int i = 0; i < list.length-1; i++){
			if(c>1)continue;
			if(list[i]==list[i+1])c++;
			if(list[i]!=list[i+1])c=1;
			if(c==1)count++;
		}
		return count;
	}
}