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

int main(int, char**)
{
    int n;

    cin >> n;

    long long result = 0;
    for (int i = 1; i <= n; i++)
        if (i % 3 != 0 && i % 5 != 0) result += i;

    cout << result << endl;

    return 0;
}