import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    } main {
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) float total_len = Float.valueOf(sc.next()); total_len Float.valueOf(sc.next()) Float.valueOf Float sc.next() sc.next sc System.out.println((total_len/3)*(total_len/3)*(total_len/3)) System.out.println System.out System System.out (total_len/3)*(total_len/3)*(total_len/3) (total_len/3)*(total_len/3)*(total_len/3) (total_len/3) total_len 3 (total_len/3) total_len 3 (total_len/3) total_len 3 String[] args args public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float total_len = Float.valueOf(sc.next());
        System.out.println((total_len/3)*(total_len/3)*(total_len/3));
    }
}