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using System;
 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Random rand = new Random();
            int number = rand.Next(20) + 1;
            Console.WriteLine("i've picked a number from 1 to 20. guess it!");
            int guess = 0;
            while (guess != number)
            {
                Console.Write("guess: ");
                string line = Console.ReadLine();
                line = line.Trim();
                bool validGuess = true;
                try { guess = int.Parse(line); }
                catch { validGuess = false; }
                if (validGuess)
                {
                    if (guess < 1 || guess > 20) Console.WriteLine("that wasn't even between 1 and 20!");
                    else if (guess != number) Console.WriteLine("that's not the number!");
                    else Console.WriteLine("you're right! it was " + number + "!");
                }
                else Console.WriteLine("that wasn't a number.");
            }
            Console.WriteLine("good job, you won!");
            Console.ReadKey();
        }
    }
}