Problem: 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

Solution (in CPP):

Solution:
//A > Bのとき難しいなあと思っていたら、A < Bやんけ！
#include <stdio.h>

double pi = 3.14159265358979;

int main() {
	double a, b;
	scanf("%lf%lf", &a, &b);
	printf("%.14f\n", 4 / 3.0 * pi * b * b * b);
	return 0;
}