import java.util.*;
public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
}

} import java.util.*; util.* java public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
}

} Main public static void main(String[] args) {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
} main {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) double l =sc.nextDouble(); l sc.nextDouble() sc.nextDouble sc double z=(double)(l/3)*(l/3)*(l/3); z (double)(l/3)*(l/3)*(l/3) (double)(l/3)*(l/3)*(l/3) (double)(l/3) l 3 (l/3) l 3 (l/3) l 3 System.out.format("%.12f",z) System.out.format System.out System System.out "%.12f" z String[] args args public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
}

} public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
}

} Main
import java.util.*;
public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);

double l =sc.nextDouble();
double z=(double)(l/3)*(l/3)*(l/3);
System.out.format("%.12f",z);
}

}