using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yuki_425
{
    class Program
    {
        static double p0, q;
        const int MAX = 20;
        static double ans = (double)1 / 3;
        static void Main(string[] args)
        {
            var t = scan;
            p0 = (double)t[0] / 100; q = (double)t[1] / 100;
            double st = (double)1 / 3;

            //はじめに必勝法

            double memo = st * p0;
            use(memo, 0,p0);

            //はじめに使わない

            memo = st * (1- p0);
            nouse(memo, 0,p0);


            Console.WriteLine(ans.ToString("F7"));
        }
        static void use(double per, int cnt,double pp)
        {
            if (cnt > MAX) return;
            ans += per / 2;
            //Console.WriteLine(per+" "+ans);
            double p = Math.Max(0, pp - q);
            use(p  * per / 2, cnt + 1, p);
            nouse((1- p) * per / 2, cnt + 1, p);
        }
        static void nouse(double per, int cnt, double pp)
        {
            if (cnt > MAX) return;
            ans += per / 3;
            //Console.WriteLine(per +" " +ans);
            double p = Math.Min(1, pp + q);
            use(p * per / 3, cnt + 1, p);
            nouse((1 - p) * per / 3, cnt + 1, p);
        }
        static int[] scan { get { return Array.ConvertAll(Console.ReadLine().Split(), int.Parse); } }
    }
}