#include <bits/stdc++.h>

using namespace std;

int main() {
  int n; cin >> n;
  unordered_map<int, int> A;
  for (int i = 0; i < n; ++i) {
    int a; cin >> a;
    A[a]++;
  }
  int ans = 0;
  for (unordered_map<int, int>::iterator it = A.begin(); it != A.end(); ++it) {
    if (it -> second == 1) ans++;
  }
  cout << ans << endl;
}