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

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var s = ReadLine().Split();
        var r = double.Parse(s[0]);
        var d = double.Parse(s[1]);
        WriteLine(Math.Sqrt(d * d - r * r).ToString("0.0000000"));        
    }
}