#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define sz(n) (int)(n).size()
using namespace std;
typedef long long ll;
typedef vector<int> VI;

int main() {
	int n;
	cin >> n;
	VI a(n);
	REP(i, n) cin >> a[i];
	a.push_back(0); a.push_back(1234567890);
	sort(a.begin(), a.end());
	int ans = 0;
	FOR(i, 1, n + 1) {
		if (a[i - 1] != a[i] && a[i] != a[i + 1]) ans++;
	}
	cout << ans << endl;
	return 0;
}