import java.util.*;

public class Main {
    public static void main(String[] args) {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    }
} Main public static void main(String[] args) {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    } main {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    } double a = new Scanner(System.in).nextDouble(); a new Scanner(System.in).nextDouble() new Scanner(System.in).nextDouble new Scanner(System.in) System.out.println(a/3 * a/3 * a/3) System.out.println System.out System System.out a/3 * a/3 * a/3 a/3 * a/3 * a a/3 * a/3 a/3 * a a/3 a 3 a 3 a 3 String[] args args public class Main {
    public static void main(String[] args) {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    }
} public class Main {
    public static void main(String[] args) {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        double a = new Scanner(System.in).nextDouble();
        System.out.println(a/3 * a/3 * a/3);
    }
}
