
class Main{
public static void main(String[]args){
  System.out.println(Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3));
}
} class Main{
public static void main(String[]args){
  System.out.println(Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3));
}
} Main public static void main(String[]args){
  System.out.println(Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3));
} main {
  System.out.println(Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3));
} System.out.println(Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3)) System.out.println System.out System System.out Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3) Math.pow Math ((double)new java.util.Scanner(System.in).nextInt())/3 ((double)new java.util.Scanner(System.in).nextInt()) new java.util.Scanner(System.in).nextInt new java.util.Scanner(System.in) 3 3 String[]args args

class Main{
public static void main(String[]args){
  System.out.println(Math.pow(((double)new java.util.Scanner(System.in).nextInt())/3,3));
}
}