using System;
using System.Linq;

public class yukicoder{
    public static void Main(){
        double n = double.Parse(Console.ReadLine());
        
        if(n == 1)
        {
            Console.WriteLine(0);
        }
        else
        {
            if(n % 2 != 0)
            {
                n++;
            }
            Console.WriteLine(Math.Ceiling(Math.Log(n, 2)));
        }
        
    }
}