## 0718. Ring

###### Time limit : 1000 ms Memory limit : 64 mb

The area of a ring and radius of an external circle are set. Define radius of an internal circle.

Input

In a unique line set 2 real numbers, at first the area of a ring and through a blank - radius of an external circle. The radius of a circle does not exceed 100.

Output

In a unique line deduce radius of an internal circle with accuracy 2 signs after a decimal point.

Samples

 № Input Output 1 50.2655 5 3.00