import java.text.DecimalFormat;
        import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    }
} import java.text.DecimalFormat; DecimalFormat java.text import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    }
} Main public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    } main {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    } Scanner in = new Scanner(System.in); in new Scanner(System.in) double s=in.nextDouble(); s in.nextDouble() in.nextDouble in DecimalFormat df = new DecimalFormat( "0.000000 "); df new DecimalFormat( "0.000000 ") System.out.println(df.format(s*s*s/27)) System.out.println System.out System System.out df.format(s*s*s/27) df.format df s*s*s/27 s*s*s s*s*s s s s 27 String[] args args public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    }
} public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    }
} Main
import java.text.DecimalFormat;
        import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double s=in.nextDouble();

        DecimalFormat df = new DecimalFormat( "0.000000 ");

        System.out.println(df.format(s*s*s/27));

    }
}
