using System;

public class Program

{

    public static void Main()

    {

    Console.WriteLine("Program calculates angle between two pipes");

    Console.WriteLine();                               

    FirstPipe();                

    string result = FirstPipe();

         if(result == "no")

         {   FirstPipe();

            }

    }

    public  static string FirstPipe()

    {

        string[] Mes1 = { 

                    "For the first pipe, choose an option:", 

                    "\r\n",

                    "Enter 1 for known chainage and invert level, or ", 

                    "Enter 2 for known gradient (don't use %)"};

        foreach (string line in Mes1)

         Console.WriteLine(line);

    int ChoiceP1 = int.Parse(Console.ReadLine());;  

        if (ChoiceP1 == 1)

        {

            Console.WriteLine("Enter chainage in m");

            double Chain1 = double.Parse(Console.ReadLine());

            Console.WriteLine("Enter Invert Level in m");

            double IL1 = double.Parse(Console.ReadLine());  

            }

         else if (ChoiceP1 == 2)

        {

             Console.WriteLine("Enter Gradient");

             double Grad1 = double.Parse(Console.ReadLine());}

         else

         {

             Console.WriteLine("You did not enter 1 or 2");

         }

    if(ChoiceP1!=1|| ChoiceP1!=2)

    {

        return "no";

    }

        else

        {

            return "yes";

        }

    }

}