using System;
class P
{
    static void Main()
    {
        double A = double.Parse(Console.ReadLine());
        int Cnt = 0;
        while (true)
        {
            if (A<=1)
            {
                Console.WriteLine(Cnt);
                break;
            }
            Cnt++;
            A /= 2;
        }
        Console.ReadKey();
    }
}