using System.Numerics;

public class Program
{
    public static void Main()
    {

        BigInteger num = BigInteger.Parse(Console.ReadLine() ?? string.Empty);
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] moji = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;

        int count = 0;
        int f = 1;
        while(f <  num)
        {
            count++;
            f *= 2;
            if(f == num-1)
            {
                count++;
                break;
            }
            if(f == num)
            {
                break;
            }
        }
        Console.WriteLine(count);
    }
}