using System;
using System.Linq;

namespace TestConsole
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = int.Parse(Console.ReadLine());
            int count = 0;

            if (input > 1)
            {
                count += (int)Math.Log((input-1), 2);
                count++;
            }
            Console.WriteLine(count);
        }
    }
}