#include<bits/stdc++.h>
using namespace std;
int main()
{
    int N;
    cin >> N;
    long long count = 0;
    for(int i = 1;i <= N;i++)
    {
        if(i % 3 == 0 or i % 5 == 0)
            continue;
        count += i;
    }
    cout << count << '\n';
    return 0;
}
