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

void solve(long long N)
{
    long long ans = 0;
    for (long long i = 0; i < N; i++)
    {
        if (i % 3 != 0 && i % 5 != 0)
        {
            ans += i;
        }
    }

    cout << ans << endl;
}

// Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
int main()
{
    long long N;
    scanf("%lld", &N);
    solve(N);
    return 0;
}