using System;

class Program
{
    static void Main(string[] args)
    {
        var X = int.Parse(Console.ReadLine());
        var current = 0;
        var distance = 0;
        var A = 2;
        var B = -1;
        var moves = new int[] { A, A, B, B, A, B, B };

        for (int i = 0; i < 100; i++)
        {
            var flag = 0;
            foreach (var move in moves)
            {
                current += move;
                distance += Math.Abs(move);
                if (current == X)
                {
                    flag = 1;
                    break;
                }
            }
            if (flag == 1) break;
        }
        Console.WriteLine(distance);
    }
}