using System;

namespace No47
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = int.Parse(Console.ReadLine());

            var pocket = 1;
            var result = 0;

            while (pocket < N)
            {
                pocket *= 2;
                result++;
            }

            Console.Write(result);
        }
    }
}