using System;                   

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Tính S(n) = CanBac2(x^n + CanBac2(x^n-1 + … + CanBac2(x^2 + CanBac2(x)))) có n dấu căn");

        Console.WriteLine("Nhap vao so x:");

        double x = int.Parse(Console.ReadLine());

        Console.WriteLine("Nhap vao so n:");

        double n = int.Parse(Console.ReadLine());

        double s=0;

        for(float i=1;i<n;i++)

        {   s=Math.Sqrt(s+Math.Pow(x,i));   

        }

        Console.WriteLine("Ket qua la:{0}",s);

    }

}