/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	

	public static void main (String[] args) throws java.lang.Exception
	{
	    Scanner sc = new Scanner(System.in);

	    // N(配列数)
	    int n = sc.nextInt();
	    //System.out.println("n=" + n);
	    
	    
	    List<Integer> list = new ArrayList<Integer>();

        int index = 0;
	    while((sc.hasNext()) && (index < n + 1)){
	        int s = sc.nextInt();
	        list.add(s);
		    index++;
	    }
	    
	    //HashSet<Integer> hashSet = new HashSet<Integer>();
        //hashSet.addAll(list);
        
        
        
		// 重複しない配列
        Set<Integer> set = new HashSet<Integer>();
		for (Integer s : list) {
			if (!set.contains(s)) {
				set.add(s);
			}
		}
		
		// 新規カウント
		int c = 0 ;
		
		for (Integer x : set) {
			int cc = Collections.frequency(list, x);
			if (cc == 1) {
				c++;
			}
		}
		
		

		System.out.println(c);
	}
	
	
	
	
		
}