using System;

public class Program

{

    public static double bai1(int n)

        {if(n==0)

            {return 1;}

         else

             {return bai1(n-1)+1/(bai1(n-1));

             }

        }

    public static int bai2(int n)

    { if(n==1||n==2)

        {return 1;

        }

     else 

        { return bai2(n-1)+bai2(n-2);

        }

    }

    public static int bai3(int a,int b)

    {

        if(b==0)

        {return a;

        }

        else

        { return bai3(b,a%b);

        }

    }

        public double bai5(double a, int n)

    {

        if (n == 0) return 1;

        else if (n % 2 == 0)

        { return Math.Pow(bai5(a,n/2),2);

        }

        else return a * Math.Pow(bai5(a,(n-1)/2),2);;

    }

    public static int bai4(int k,int n)

    { 

        if( k==n||k<0)

        {return 1;

        }

        else

        { return bai4(k,n-1)+bai4(k-1,n-1);

        }

    }

        public static void Main(string[] args)

        {

            //Your code goes here

            int n=5;

            double c=bai1(n);

            Console.Write(c);

            Console.WriteLine("Hello, world!");

        }

}