using System;

​

public class Program

{

    public static void Main()

    {

            string restart = " ";

            while (restart != "x" && restart != "X")

            {

            Console.WriteLine("How many Fibonacci numbers would you like to output?");

            int n;

            string x = Console.ReadLine();

            if (int.TryParse(x, out n))

            {

            }

            else 

            {

                    Console.WriteLine("Error");

            }

                ulong F1 = 1, F2 = 2;

                Console.Write("The first " + n + " Fibonacci numbers are 1, 1");

                int i = 1;

                while (i <= n - 2)

                {

                    ulong Fn = F1 + F2;

                    Console.Write(", " + Fn);

                    F1 = F2;

                    F2 = Fn;

                    i++;

                }

                Console.WriteLine("Press 'x' to quit, or any other value to restart");

                restart = Console.ReadLine();   

            }

    }   

}