#include <algorithm>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <sstream>
#include <functional>
#include <map>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <list>
#include <numeric>
using namespace std;
const double PI = 3.14159265358979323846;
const double EPS = 1e-12;
const int INF = 1<<30;
typedef pair<int,int> P;
typedef long long ll;
typedef unsigned long long ull;


int main(){
	int n;
	cin>>n;
	vector<ll> d(n+2);
	for(int i = 0; i < n; i++) cin>>d[i];
	d[n] = 0; d[n+1] = 100LL*INF;
	sort(d.begin(), d.end());
	int res = 0;
	for(int i = 1; i <= n; i++){
		if(d[i-1]!=d[i] && d[i]!=d[i+1]) res++;
	}
	cout<<res<<endl;

	return 0;
}