#include <iostream>
#define rep(i, N) for(int i = 0; i < N; ++i)
using namespace std;

typedef long long ll;
int main()
{
    ll n;
    cin >> n;

    ll sum = 0;
    for(ll i = 1; i <= n; i++)
    {
        if((i % 3 != 0) && (i % 5 != 0))
        {
            sum += i;
        }
    }
    cout << sum << endl;
    return 0;
}
