#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(){
   int ans = 0,anum,n;
   cin >> n;
   vector<long long> a;
   for(int i = 0;i < n;i++) cin >> a[i];
   for(int i = 0;i < n;i++){
      anum = a[i];
      if(count(a.begin(),a.end(),anum) == 1) ans++;
   }
   cout << ans << endl;
}