import java.text.DecimalFormat;import java.util.Scanner;public class Main{	public static double PI = 3.1415927;	public static void main(String []args){		Scanner scan = new Scanner(System.in);		DecimalFormat df = new DecimalFormat("0.000");		while(scan.hasNext()){			double r = scan.nextDouble();			double factor = PI*4/3*(Math.pow(r, 3));			System.out.PRintln(df.format(factor));		}	}	}