#include <iostream>
#include <iterator>
#include <algorithm>
#include <vector>

int main(){
  std::vector<int> vc;
  size_t N;
  std::cin >> N;
  vc.resize(N);
  for(auto& elm: vc ){
        std::cin>> elm;
  }
  std::vector<int> vc2;
  const int dead_value(0);
  vc2.resize(vc.size(),dead_value);
  std::sort( std::begin(vc), std::end(vc));
  std::unique_copy(std::begin(vc),std::end(vc),std::begin(vc2) );
  std::unique( std::begin(vc2), std::end(vc2) );
  size_t cnt{0};
  for(const auto& elm:vc2){
     if(elm == 0)break;
     if(1==count_if( std::begin(vc), std::end(vc) ,[=](const int i)->bool{return i==elm;})){
        cnt++;
     }
  }
  std::cout<<cnt<<std::endl;

}