#include <algorithm>
#include <cmath>
#include <iostream>
#include <string>
#include <string.h>
#include <vector>
using namespace std;
typedef long long ll;

int main(){
    ll N;
    ll ans = 0;

    cin >> N;

    for(ll i = 1; i < N + 1; i++){
        if(i % 3 != 0 && i % 5 != 0){
            ans += i;
        }
    }

    cout << ans << endl;

    return 0;
}
