#define _USE_MATH_DEFINES
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>

#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;

int main() {
	int n;
	cin >> n;
	vector<int> a(n);
	int b[1000000010];
	rep(i, n) cin >> a[i];

	rep(i, n) b[a[i]]++;
	int cnt = 0;
	rep(i, 1000000001) if (b[i] == 1) cnt++;
	cout << cnt << endl;
	return 0;
}