import java.util.*;

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

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