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

int main()
{
    int n;
    cin >> n;
    int a[n];
    for(int i = 0; i < n; i++)
        cin >> a[i];

    sort(a,a+n);

    int ans = n;
    
    for(int i = 0; i < n; i++){
        if(a[i+1] == a[i]){
            ans--;
            if(a[i-1] != a[i]) ans--;
        }
    }

    cout << ans <<endl;

    return 0;
}