#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) cin >> arr[i];
  sort(arr, arr + n);
  int count = 0;
  int last = 0;
  for (int i = 0; i < n; i++) {
    int x = arr[i];
    if (x != 0 && x != last) count++;
    last = x;
  }
  cout << count;
}
