#include <iostream>
#include <algorithm>
using namespace std;
static const int MAX = 1000000000;

int main(){
  int N;
  cin >> N;
  int A[N + 2];
  A[0] = 0;
  A[N + 1] = MAX + 1;
  for(int i = 1; i <= N; i++)
    cin >> A[i];
  sort(A, A + N + 2);
  int result = 0;
  for(int i = 1; i <= N; i++){
    if(A[i] != A[i - 1] && A[i] != A[i + 1])
      result++;
  }
  cout << result << endl;
}