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

class Program
{
    static int NN => int.Parse(ReadLine());
    static double[] NList => ReadLine().Split().Select(double.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (p, q) = (c[0] / 100, c[1] / 100);
        WriteLine(p * q / (p * q + (1 - p) * (1 - q)) * 100);
    }
}