using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Magatro
{
    static void Main()
    {
        long N = long.Parse(Console.ReadLine());
        long cnt = 0;
        cnt += N / 3;
        cnt += N / 5;
        Console.WriteLine(cnt * 2);
    }

}