import java.math.BigDecimal;
import java.util.*;
public class Main {

	public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	}

	private static BigDecimal find(double num) 
	{
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	}

} import java.math.BigDecimal; BigDecimal java.math import java.util.*; util.* java public class Main {

	public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	}

	private static BigDecimal find(double num) 
	{
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	}

} Main public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	} main {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) double num=sc.nextDouble(); num sc.nextDouble() sc.nextDouble sc System.out.println(find(num)) System.out.println System.out System System.out find(num) find num String[] args args private static BigDecimal find(double num) 
	{
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	} find {
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	} double d=num/3; d num/3 num 3 BigDecimal b=BigDecimal.valueOf(d); b BigDecimal.valueOf(d) BigDecimal.valueOf BigDecimal d BigDecimal c=b.multiply(b); c b.multiply(b) b.multiply b b b=c.multiply(b) b c.multiply(b) c.multiply c b return (b); (b) double num num public class Main {

	public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	}

	private static BigDecimal find(double num) 
	{
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	}

} public class Main {

	public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	}

	private static BigDecimal find(double num) 
	{
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	}

} Main
import java.math.BigDecimal;
import java.util.*;
public class Main {

	public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		double num=sc.nextDouble();
		System.out.println(find(num));
	}

	private static BigDecimal find(double num) 
	{
		// TODO Auto-generated method stub
		double d=num/3;
		BigDecimal b=BigDecimal.valueOf(d);
		BigDecimal c=b.multiply(b);
		b=c.multiply(b);
		
		return (b);
		
	}

}
