Take as an input an odd number and print the absolute value of it. If the number is even, print "Please write an odd number." and continue reading numbers.
using System;

namespace _11._Odd_Number
{
    class OddNumber
    {
        static void Main(string[] args)
        {
            int n = Math.Abs(int.Parse(Console.ReadLine()));

            while (true)
            {
                if (n % 2 == 0 )
                {
                    Console.WriteLine("Please write an odd number.");
                }
                else
                {
                    Console.WriteLine($"The number is: {n}");
                    break;
                }
                n = Math.Abs(int.Parse(Console.ReadLine()));
            }
        }
    }
}