using System;

public class Program

{   static double TongChia(int n)

    {double s=0;

    for(int i=0;i<=n;i++)

    {s=s+(1.0*(2*i+1))/(2*i+2);}

     return s;

    }

    public static void Main()

    {

        //Tính S(n) = ½ + ¾ + 5/6 + … + 2n + 1/ 2n + 2

        Console.WriteLine("Nhap N:");

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

        double s=0;

        for(int i=0;i<=n;i++)

        {s=s+(1.0*(2*i+1))/(2*i+2);

        }

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

        double t=TongChia(n);

        Console.WriteLine("Kiem tra Ham {0}",t);

    }

}