using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		double[] ab = Console.ReadLine().Split().Select(i => double.Parse(i))
			.OrderByDescending(i => i).ToArray();
		double a = ab[0], b = ab[1];
		Console.WriteLine(Math.Sqrt(a * a - b * b).ToString("F6"));
	}
}