#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000 * 1000 * 1000 + 7;
const double pi = acos(-1.0);
const double eps = 1e-9;
const long long inf = 1e18;
int toint(string s) {
  int sm;
  stringstream ss(s);
  ss >> sm;
  return sm;
}
long long tolint(string s) {
  long long sm;
  stringstream ss(s);
  ss >> sm;
  return sm;
}
long long a, b, c, d, e, f, g, h, l, m, n, p, q, r, t, u, w, x, y, z,
    ara[100005] = {0}, arr[100005] = {0};
vector<long long> v, v2, v3;
string s;
int main() {
  cin.tie(0);
  cout.sync_with_stdio(0);
  cin >> n;
  map<int, int> mp;
  b = 0;
  for (int i = 1; i <= (n); i++) {
    cin >> a;
    if (mp[a] == 0 && a != 0) {
      mp[a] = 1;
      b++;
    }
  }
  cout << b;
}
