using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var va = Console.ReadLine().Split().Select(double.Parse).ToArray();
            double dn = Math.Sqrt(va[1] * va[1] - va[0] * va[0]);
            Console.WriteLine(dn);
            Console.ReadLine();
        }
    }
}