using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using static System.Math;

namespace SortItems
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = BigInteger.Parse(Console.ReadLine());
            var cnt = (n / 3) * 2 + (n / 5) * 2;

            Console.WriteLine(cnt);

        }
    }
}