using System;
using System.Linq;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var line1 = int.Parse(Console.ReadLine());

            var n = line1;
            int result = 0;
            int biscuit = 1;

            while (true)
            {
                if (biscuit >= n)
                {
                    break;
                }
                result++;
                biscuit = 2 * biscuit;
            }

            //結果を表示
            Console.WriteLine(result);
        }
    }
}