using System;
using System.Collections.Generic;
using System.Linq;

class Solution
{
    static void Main()
    {
        var vals = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        int m = vals[0];
        int n = vals[1];
        double expect = m;

        for(int i = 0; i < n;i++)
        {
            var next = new double[3];
            next[0] = expect * 2;
            next[1] = expect + 1;
            next[2] = 0;
            expect = next.Average();
        }

        Console.WriteLine(expect);
    }
}