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

int main()
{
    long long n;
    long long sum = 0;
    cin >> n;
    for (long long i = 1; i <= n; i++) {
        if(i%3!=0&&i%5!=0) sum += i;
    }
    cout << sum << endl;
    return 0;
}

