#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main(){
    int N,cnt=0;
    cin >> N;
    vector<int> A(N+2);
    A[0]=0;A[N+1]=1e9+1;
    for(int i=1;i<=N;i++)cin >> A[i];
    sort(A.begin(),A.end());
    for(int i=1;i<=N;i++){
        if(A[i]!=A[i+1] && A[i]!=A[i-1])cnt++;
    }
    cout << cnt << endl;
    return 0;
}