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