The three found themselves in a peculiar grove. The trees here grew in perfectly geometric formations, and the leaves themselves held strange, mathematical properties. Omar, ever the observant one, noticed that a particular pattern of glowing moss on the ground formed a perfect isosceles triangle.
Sam07a, recalling tales of the Unknown's hidden truths, explained that within this grove, every significant geometric shape had two special points: its "Heart" (the center of its inscribed circle, or incenter) and its "Soul" (the center of its circumscribed circle, or circumcenter). The distance between these two points, he claimed, held the key to unlocking the grove's path.
This particular isosceles triangle, formed by the moss, had a base of length $$$B$$$ and two equal legs of length $$$L$$$. sam07a needed to determine the distance d between its Heart and its Soul.
"The Unknown reveals its paths not by light, but by understanding," Sam07a murmured, sketching in the dirt. "If we know the lengths of this triangle's base and legs, can we find the distance between its Heart and Soul?"
The single line of input contains two integers, $$$L$$$ and $$$B$$$ $$$(1 \le B , L \le 10^6)$$$, representing the length of the leg and the base of the isosceles triangle, respectively.
if no such triangle exists print $$$-1$$$ otherwise print the distance d between the circumcenter and incenter of the triangle. Your answer will be considered correct if its absolute or relative error does not exceed $$$10^{-6}$$$.
8 5
1.579084068
5 14
-1
Incenter: The center of the inscribed circle (the largest circle that fits inside the triangle, touching all three sides).
Circumcenter: The center of the circumscribed circle (the circle that passes through all three vertices of the triangle).
