#include <iostream>
#include <iterator>
#include <algorithm>
//#include <vector>
#include<list>
int main(){
  std::cout.sync_with_stdio(false);
    
  //std::vector<int> vc;
  std::list<int> vc;
  size_t N;
  std::cin >> N;
//  vc.reserve(N);
  int temp;
  std::cin>>temp;
  vc.push_back(temp);
  
  size_t cnt{1};
  for(size_t s; s<N-1;s++){
    std::cin>>temp;
    size_t a = count(std::begin(vc),std::end(vc),temp);
    if(0 == a){    
        vc.push_back(temp);  
        cnt++;
    }
    if(1 == a){
        vc.push_back(temp);
        cnt--;
    }
  }
  std::cout<<cnt<<std::endl;
}