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:
//=================================
// Created on: 2018/09/19 15:36:13
//=================================
#include <bits/stdc++.h>
using ld = long double;
constexpr ld PI = 3.14159265359;
int main()
{
    ld a, b;
    std::cin >> a >> b;
    std::cout << std::fixed << std::setprecision(15) << b * b * b * 4 / 3 * PI << std::endl;
    return 0;
}