using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;
using static System.Console;
using static System.Math;

class Program
{
    static void Main(string[] args)
    {
        int N = int.Parse(ReadLine());
        int count = 0;
        int n = 1;
        while(N > n)
        {
            n *= 2;
            count++;
        }
        WriteLine(count);
    }
}