import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		        Scanner sc = new Scanner(System.in);
		        double cm = sc.nextDouble();

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        }

	}

 import java.math.BigDecimal; BigDecimal java.math import java.math.RoundingMode; RoundingMode java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		        Scanner sc = new Scanner(System.in);
		        double cm = sc.nextDouble();

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        }

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

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        } main {
		        Scanner sc = new Scanner(System.in);
		        double cm = sc.nextDouble();

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) double cm = sc.nextDouble(); cm sc.nextDouble() sc.nextDouble sc double a =0; a 0 double b = 0; b 0 double c =0; c 0 double Volume  = 0; Volume 0 a = cm/3 a cm/3 cm 3 b = cm/3 b cm/3 cm 3 c = cm/3 c cm/3 cm 3 if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        } a ==b &&  b == c a ==b a b b == c b c {
		        	Volume = a*b*c;
		        } Volume = a*b*c Volume a*b*c a*b*c a b c BigDecimal volume = new BigDecimal(String.valueOf(Volume)); volume new BigDecimal(String.valueOf(Volume)) BigDecimal anser = volume.setScale(12, RoundingMode.DOWN); anser volume.setScale(12, RoundingMode.DOWN) volume.setScale volume 12 RoundingMode.DOWN RoundingMode RoundingMode.DOWN System.out.println(anser) System.out.println System.out System System.out anser String[] args args public class Main {
	public static void main(String[] args) {
		        Scanner sc = new Scanner(System.in);
		        double cm = sc.nextDouble();

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        }

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

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        }

	} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		        Scanner sc = new Scanner(System.in);
		        double cm = sc.nextDouble();

		        double a =0;
		        double b = 0;
		        double c =0;
		        double Volume  = 0;
		        a = cm/3;
		        b = cm/3;
		        c = cm/3;
		        /*while(a != b && b != c && c != (cm/3)) {

		        }*/
		        if(a ==b &&  b == c) {
		        	Volume = a*b*c;
		        }
		        BigDecimal volume = new BigDecimal(String.valueOf(Volume));
		        BigDecimal anser = volume.setScale(12, RoundingMode.DOWN);
		        System.out.println(anser);		        }

	}


