import java.util.*;

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

public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		System.out.println(Math.pow(l / 3, 3));
	}
}