using System;
using System.Collections.Generic;
using static System.Console;
namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] yuki = ReadLine().Split(' ');
            int N = int.Parse(yuki[0]);
            int K = int.Parse(yuki[1]);
            if(N < K)
            {
                WriteLine(0);
                return;
            }
            double a = Math.Pow(2, K);
            double b = Math.Pow(2, N);
            if(a == 1)
            {
                WriteLine(b);
                return;
            }
            WriteLine(b / a);
        }
    }
}