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

int main()
{
    int n;
    long long sum = 0;
    cin >> n;
    for(int i = 1; i <= n; i++)
    {
        if(i % 3 == 0 || i % 5 == 0)
            continue;
        sum += i;
    }
    cout << sum;
    return 0;
}