using System;

class Program

{

  static void Main()

  {

    int H = int.Parse(Console.ReadLine());

    double p = 0;

    int count = 0;

    for (int i = 0;p < H;i++)

    {

      p += Math.Pow(2, i);

      count++;

    }

    Console.WriteLine(count);

  }

}