using System;
using System.Linq;
 
class Program
{
	static void Main()
	{
		var line = Console.ReadLine();
        var query =
            from x in line.Trim().Split(' ')
            select double.Parse(x);
        var list = query.ToList();
 
        double r = list[0], d = list[1];
        double ans = Math.Sqrt(d * d - r * r);
 
        Console.WriteLine(ans);
	}
}