#include <bits/stdc++.h>
using namespace std;
int main() {
  set<int> a;
  int n, t;
  cin >> n;
  while (n--) {
    cin >> t;
    a.insert(t);
  }
  cout << ((a.count(0) == 1) ? a.size() - 1 : a.size());
  return 0;
}
