func main()
	var ss: [][]char :: cui@input().split(" ")
	var r: float :: ss[0].toFloat(&)
	var d: float :: ss[1].toFloat(&)
	var ans: float :: (d ^ 2.0 - r ^ 2.0) ^ 0.5
	do cui@print("\{ans.toStrFmt(".10f")}\n")
end func