05. Invalid Number

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace invalidNumber
{
    class invalidNumber
    {
        static void Main(string[] args)
        {
            var num = int.Parse(Console.ReadLine());

            if ((num >= 100) && (num <= 200))
            {
                Console.WriteLine();
            }
            else if (num == 0)
            {
                Console.WriteLine();
            }
            else
            {
                Console.WriteLine("invalid");
            }
        }
    }
}