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

int main()
{
    int n;
    cin >> n;

    long long sum = 0;

    for (int i = 1; i <= n; ++i)
    {
        if (i % 3 != 0 && i % 5 != 0)
        {
            sum += i;
        }
    }

    cout << sum << endl;
}