#include <iostream>

using namespace std;

typedef long long ll;


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

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

    cout << total << endl;
}
