#include <bits/stdc++.h>
using namespace std;
int main()
{
    long long int n;
    cin >> n;
    long long int sum = 0;
    for (long long int i = 1; i <= n; i++)
    {
        if (i % 3 != 0 && i % 5 != 0)
        {
            sum = sum + i;
            //cout << i << " ";
        }
    }
    cout << sum << endl;
}