import java.math.BigDecimal;
import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    }
} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    }
} Main public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    } main {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) double d = scan.nextDouble(); d scan.nextDouble() scan.nextDouble scan double v = (d/3)*(d/3)*(d/3); v (d/3)*(d/3)*(d/3) (d/3)*(d/3)*(d/3) (d/3) d 3 (d/3) d 3 (d/3) d 3 System.out.println(v) System.out.println System.out System System.out v String[] args args public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    }
} public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    }
} Main
import java.math.BigDecimal;
import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double d = scan.nextDouble();
        double v = (d/3)*(d/3)*(d/3);
        System.out.println(v);
    }
}