#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int main(){
double r,v;
scanf("%lf",&r);
v = 4.0/3.0*3.14*pow(r,3);
printf("%.5lf",v);
return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int r;
    cin>>r;
    double sum = 1;
    sum = 4.0/3*3.14*r*r*r;
    printf("%.5f",sum);
    return 0;
}