#include <iostream>
#include <map>

using namespace std;

int main(int argc, const char* argv[])
{
	int N;
	cin >> N;
	map<int, int> m;
	int a;
	for (int i = 0; i < N; i++) {
		cin >> a;
		m[a]++;
	}
	int cnt = 0;
	for (auto&& v : m) cnt += v.second == 1;
	cout << cnt << endl;
	return 0;
}