using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter some text:");

        string input = Console.ReadLine();

        if (input.Length == 0 || input == null)

        {

            throw new ArgumentException("You did something wrong.");

        } else 

        {

            Console.WriteLine("You entered: " + input.ToString());

        }

    }

}