Problem F: Beavergnaw
## Problem F: Beavergnaw

When chomping a tree the beaver cuts a very specific shape out of the
tree trunk. What is left in the tree trunk looks like two frustums
of a cone joined by a cylinder with the diameter the same as its
height. A very curious beaver tries not to demolish a tree but rather
sort out what should be the diameter of the cylinder joining the
frustums such that he chomped out certain amount of wood. You
are to help him to do the calculations.
We will consider an idealized beaver chomping an idealized tree. Let
us assume that the tree trunk is a cylinder of diameter **D** and
that the beaver chomps on a segment of the trunk also of height
**D**. What should be the diameter **d** of the inner cylinder
such that the beaver chmped out **V** cubic units of wood?

Input contains multiple cases each presented on a separate line. Each
line contains two integer numbers **D** and **V** separated by
whitespace. **D** is the linear units and **V** is in cubic
units. **V** will not exceed the maximum volume of wood that the
beaver can chomp. A line with **D**=0 and **V**=0 follows the
last case.

For each case, one line of output should be produced
containing one number rounded to three fractional digits giving
the value of **d** measured in linear units.

### Sample input

10 250
20 2500
25 7000
50 50000
0 0

### Output for sample input

8.054
14.775
13.115
30.901