using System;

​

public class Program

{

    public static void Main()

    {

        start:

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

        string x = Console.ReadLine();

        ulong n;

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

        {

            ulong F1 = 1, F2 = 1;

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

            ulong i = 1;

            while (i <= n - 2)

            {

                ulong Fn = F1 + F2;

                Console.Write(", " + Fn);

                F1 = F2;

                F2 = Fn;

                i++;

            }

        }

        else

        {

            Console.WriteLine("Your input isn't valid. Please enter a number");

            goto start;

        }

​

        Console.WriteLine(" ");

        Console.WriteLine("Would you like to run the program again? y/n");

        string choice = Console.ReadLine();

        if (choice == "y" || choice == "y")

        {

            Console.Clear();

            goto start;

        }

        else

        {

            Console.Clear();

        }

    }

}