#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <map>
#include <algorithm>

using namespace std;

int main() {
	int n;
	cin >> n;

	vector<int>a(n);
	map<int, int>aMap;

	for (int i = 0; i < n; i++) {
		cin >> a[i];
		aMap[a[i]]++;
	}

	int ans = 0;

	for (map<int, int>::iterator it = aMap.begin(); it != aMap.end(); ++it) {
		if ((*it).second == 1) ans++;
	}

	cout << ans << endl;
	return 0;
}