Right triangle

problem

Given the lengths of $2$ sides that are not the hypotenuse of a right triangle, $A$ and $B$. The side of length $A$ overlaps the $x$ axis, and the side of length $B$ overlaps the $y$ axis.

Do the following:

1. Rotate the triangle around the $x$ axis.
2. Rotate the shape created by performing the operation $1$ around the $y$ axis.

Perform the operation $2$ to find the volume of the created figure.

output

Output the volume of the figure. Also, output a line break at the end. Absolute or relative errors less than $0.000001$ are allowed.

Example

Input

1 2

Output

33.510322

inputFormat

outputFormat

output

Output the volume of the figure. Also, output a line break at the end. Absolute or relative errors less than $0.000001$ are allowed.

Example

Input

1 2

Output

33.510322

样例

1 2

33.510322