import java.util.*;

class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int leng = scan.nextInt();
        scan.close();
        double result = 0.0;

        double amari = leng % 3;
        double qubeAmari = amari / 3;

        double qubeLength = leng - amari;
        qubeLength = qubeLength / 3;

        if(leng >= 3){result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);}
        else {result = qubeAmari * qubeAmari * qubeAmari;}

        System.out.println(String.format("%.12f", result));
    }
} import java.util.*; util.* java class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int leng = scan.nextInt();
        scan.close();
        double result = 0.0;

        double amari = leng % 3;
        double qubeAmari = amari / 3;

        double qubeLength = leng - amari;
        qubeLength = qubeLength / 3;

        if(leng >= 3){result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);}
        else {result = qubeAmari * qubeAmari * qubeAmari;}

        System.out.println(String.format("%.12f", result));
    }
} Main public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int leng = scan.nextInt();
        scan.close();
        double result = 0.0;

        double amari = leng % 3;
        double qubeAmari = amari / 3;

        double qubeLength = leng - amari;
        qubeLength = qubeLength / 3;

        if(leng >= 3){result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);}
        else {result = qubeAmari * qubeAmari * qubeAmari;}

        System.out.println(String.format("%.12f", result));
    } main {
        Scanner scan = new Scanner(System.in);
        int leng = scan.nextInt();
        scan.close();
        double result = 0.0;

        double amari = leng % 3;
        double qubeAmari = amari / 3;

        double qubeLength = leng - amari;
        qubeLength = qubeLength / 3;

        if(leng >= 3){result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);}
        else {result = qubeAmari * qubeAmari * qubeAmari;}

        System.out.println(String.format("%.12f", result));
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int leng = scan.nextInt(); leng scan.nextInt() scan.nextInt scan scan.close() scan.close scan double result = 0.0; result 0.0 double amari = leng % 3; amari leng % 3 leng 3 double qubeAmari = amari / 3; qubeAmari amari / 3 amari 3 double qubeLength = leng - amari; qubeLength leng - amari leng amari qubeLength = qubeLength / 3 qubeLength qubeLength / 3 qubeLength 3 if(leng >= 3){result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);}
        else {result = qubeAmari * qubeAmari * qubeAmari;} leng >= 3 leng 3 {result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);} result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari) result (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari) (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari) (qubeLength + qubeAmari) qubeLength qubeAmari (qubeLength + qubeAmari) qubeLength qubeAmari (qubeLength + qubeAmari) qubeLength qubeAmari {result = qubeAmari * qubeAmari * qubeAmari;} result = qubeAmari * qubeAmari * qubeAmari result qubeAmari * qubeAmari * qubeAmari qubeAmari * qubeAmari * qubeAmari qubeAmari qubeAmari qubeAmari System.out.println(String.format("%.12f", result)) System.out.println System.out System System.out String.format("%.12f", result) String.format String "%.12f" result String[] args args
import java.util.*;

class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int leng = scan.nextInt();
        scan.close();
        double result = 0.0;

        double amari = leng % 3;
        double qubeAmari = amari / 3;

        double qubeLength = leng - amari;
        qubeLength = qubeLength / 3;

        if(leng >= 3){result = (qubeLength + qubeAmari) * (qubeLength + qubeAmari) * (qubeLength + qubeAmari);}
        else {result = qubeAmari * qubeAmari * qubeAmari;}

        System.out.println(String.format("%.12f", result));
    }
}