#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	map<int, int> m;
	set<int> s;
	int N, A;
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> A;
		if (s.find(A) == s.end()) {
			s.insert(A);
			m[A] = 1;
		}else{
			m[A]++;
		}
	}

	int cnt = 0;
	set<int>::iterator it = s.begin();
	while (it != s.end()) {
		if (m[(*it)] == 1) cnt++;
		it++;
	}

	cout << cnt << endl;

	return 0;
}