using System;
class Program
{
    static void Main(string[] args)
    {
        string text=  Console.ReadLine();
        long InputNo = long.Parse(text);
        const int Fizz = 2;
        const int Buzz = 2;
        Console.WriteLine((InputNo/3)* Fizz+ (InputNo / 5)*Buzz);
        Console.ReadLine();
    }
}