import java.util.*;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    }
} Main public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    } main {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) Double L = Double.parseDouble(scanner.next()); L Double.parseDouble(scanner.next()) Double.parseDouble Double scanner.next() scanner.next scanner 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) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    }
} public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        Double L = Double.parseDouble(scanner.next());
        System.out.println(Math.pow(L/3, 3));
    }
}
