#include <bits/stdc++.h>
using namespace std;

int main() {
  int N;
  cin >> N;
  vector<int> A(N);
  for (int i = 0; i < N; i++) cin >> A.at(i);
  sort(A.begin(), A.end());
  A.push_back(0);

  int cnt = 1, ans = 0;
  for (int i = 0; i < N; i++) {
    if (A.at(i) == A.at(i + 1)) cnt++;
    else {
      if (cnt == 1) ans++;
      cnt = 1;
    }
  }

  cout << ans << "\n";
}