#include <bits/stdc++.h>
using namespace std;

int main(){
    long long N;
    cin >> N;

    long long sum = 0;

    for (long long i = 1; i <= N; i++){
        if (i % 3 == 0 || i % 5 == 0){
            sum += 0;
        }
        else {
            sum += i;
        }
    }
    cout << sum << endl;
}
