acm2002

/**
 * 求球的体积
 */
import java.util.*;
public class acm2002 {


/**
* @param args
*/
public static void main(String[] args) {
Scanner in=new Scanner (System.in);
double PI= 3.1415927;
while(in.hasNextDouble()){
double r=in.nextDouble();
double V=PI*r*r*r*4/3.0;
System.out.printf("%.3f",V);
System.out.println();
}


}


}