import java.util.*;

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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double L = sc.nextDouble();
        double a = L/3;
        double ans = a*a*a;
        
        System.out.println(ans);
        
    }
}
