#include <bits/stdc++.h>

inline long nextInt(void) {
  long temp;
  std::cin >> temp;
  return temp;
}

int main() {

  int N;
  int ans = 0;
  std::vector<long> v;

  std::cin >> N;
  for(int i = 0; i < N; ++i) {
    v.push_back( nextInt() );
  }

  std::sort(v.begin(), v.end());

  v.push_back(-1);

  for(int i = 0; i < N; ++i) {
    for(int j = i+1; j <= N; ++j) {
      if( v[i] != v[j] ) {
	if( j - i == 1 ) {
	  ++ans;
	}
	i = j - 1;
	break;
      }
    }
  }

  std::cout << ans << std::endl;
  
  return 0;
}