using System;

public class Program

{

    public static void Main()

    {

        start:

        Console.WriteLine("Please enter a number");

        string x = Console.ReadLine();

        int y;

        if(int.TryParse(x, out y)) {

        int F1 = 1, F2 = 1;

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

        int i = 1;

        while(i <= y-2)

            {int Fn = F1 + F2;

             Console.Write(", " + Fn);

             F1 = F2;

             F2 = Fn;

             i++;

            }

        }

        else {

        Console.WriteLine("Please enter a number");

        Console.ReadLine();

        goto start;

        }

    }

}

​