Number from 0 to 9 to text

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

namespace Numbers_by_words
{
    class Program
    {
        static void Main(string[] args)
        {
            int num = int.Parse(Console.ReadLine());
            string[] tonine = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
            if (num >= 0 && num <= 9)
            {
                Console.WriteLine(tonine[num]);
            }
            else if (num > 9)
            {
                Console.WriteLine("number too big");
            }
        }
    }
}