#include <iostream>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <string>
#include <vector>
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) continue;
        else sum += i;
    }
    cout << sum << endl;
    return 0;
}
