using System;
using System.Linq;

public class Program
{
    public static void Main(string[] args)
    {
        var line = Console.ReadLine().Split().Select(x => double.Parse(x)).ToArray();
        var r = line[0];
        var d = line[1];
        var al = Math.Sqrt(Math.Pow(d, 2) - Math.Pow(r, 2));
        Console.WriteLine("{0:f12}",al);
    }
}