import java.util.*;
import java.lang.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        double l = Double.parseDouble(scanner.next());
        double total = l /3;


        System.out.println(Math.pow(total, 3));
    }
} import java.util.*; util.* java import java.lang.*; lang.* java import java.util.stream.*; stream.* 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());
        double total = l /3;


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


        System.out.println(Math.pow(total, 3));
    } main {
        //コード
        Scanner scanner = new Scanner(System.in);
        double l = Double.parseDouble(scanner.next());
        double total = l /3;


        System.out.println(Math.pow(total, 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 double total = l /3; total l /3 l 3 System.out.println(Math.pow(total, 3)) System.out.println System.out System System.out Math.pow(total, 3) Math.pow Math total 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());
        double total = l /3;


        System.out.println(Math.pow(total, 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());
        double total = l /3;


        System.out.println(Math.pow(total, 3));
    }
} Main
import java.util.*;
import java.lang.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        double l = Double.parseDouble(scanner.next());
        double total = l /3;


        System.out.println(Math.pow(total, 3));
    }
}
