"acm第7题"

#include "pch.h"
#include <iostream>
#include<iomanip>
using namespace std;
int main()
{
	const double PI = 3.1415927;
	double r;
	while (cin >> r)
	{
		cout <<setiosflags(ios::fixed)<<setprecision(3)<< (4 / 3.0) *PI*r*r*r << endl;
	}
	return 0;
}