该题java版本题解

import java.util.Scanner;
public class Main{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        double n = sc.nextInt();
        double num = Math.pow(n,1/3.0);
        num=num+num+num;
        System.out.printf("%.3f",num);
    }
}