using System;
using System.Linq;
using System.Collections.Generic;

class Program
{
    /// <summary>
    /// プログラムのエントリポイント
    /// </summary>
    /// <param name="args"></param>
    static void Main(string[] args)
    {
        long max = long.Parse(Console.ReadLine());

        var result = 0;
        for (long i = 3; i <= max; i += 3)
            result += 2;

        for (long i = 5; i <= max; i += 5)
            result += 2;

        Console.WriteLine(result);
    }
}