using System;

public class Program

{

    public static void Main()

    {

        string number;

            int inputNumber;

            int temporary;

            int sum = 0;

​

            Console.WriteLine("Happy Numbers\n");

​

            Console.Write("Enter a number: ");

            number = Console.ReadLine();

​

            if (Int32.TryParse(number, out inputNumber) == true)

            {

                if (inputNumber <= 0)

                {

                    Console.WriteLine("Zero and negative input is not allowed.");

                }

                else

                {

                    while (inputNumber != 1 || inputNumber != 4)

                    {

                        for (int i = 1; i < 5; i++)

                        {

                            temporary = inputNumber % 10;

                            sum = sum + (temporary * temporary);

                            inputNumber = inputNumber / 10;

                        }

                        inputNumber = sum;

                    }

​

                    if (sum == 1)

                    {

                        Console.WriteLine("This is a happy number.");

                    }

                    else

                    {

                        Console.WriteLine("This is not a happy number.");

                    }

                }

            }

            else

            {

                Console.WriteLine("Invalid input. Enter a numeric value.");

            }

    }

}