using System;
using static System.Console;
using static System.Math;

public class Hello{
    public static void Main(){
        string[] input = ReadLine().Split(' ');
        double r = double.Parse(input[0]);
        double d = double.Parse(input[1]);
        double al = (d*d) - (r*r);
        al = Sqrt(al);
        WriteLine(al);
    }
}