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

class Program
{
    static int NN => int.Parse(ReadLine());
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var p = double.Parse(ReadLine());
        var q = double.Parse(ReadLine());
        var len = new double[n * 2 + 1];
        len[0] = 1;
        for (var u = 0; u < 100000; ++u)
        {
            var nlen = new double[n * 2 + 1];
            nlen[n] = len[n];
            nlen[n + 1] = len[n + 1];
            for (var i = 0; i < n; ++i)
            {
                nlen[i + 1] += len[i] * q;
                nlen[i + n + 1] += len[i] * p;
                if (i > 0)
                {
                    nlen[i + n] += len[i + n + 1] * q;
                    nlen[i] += len[i + n + 1] * p;
                }
            }
            len = nlen;
        }
        var ans = len[n + 1];
        for (var i = 0; i < len.Length; ++i)
        {
            if (i == n || i == n + 1) continue;
            ans += len[i] * len[n + 1] / (len[n] + len[n + 1]);
        }
        WriteLine(ans);
    }
}