Enter the string of odd numbers

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

namespace string_of_odd_numbers
{
    class Program
    {
        static void Main(string[] args)
        {
            string s;
            char[,] box;
            Console.WriteLine("Enter the string of odd Numbers");
            s = Console.ReadLine();
            int length = s.Length;
            int central = length / 2;
            box = new char[length, length];

            for (int i = 0; i < s.Length; i++)
            {
                for (int j = 0; j < s.Length; j++)
                {
                    if(i == central)
                    {
                        box[i, j] = s[j];
                    }
                    if(j == central)
                    {
                        box[i, j] = s[i];
                    }
                    if(i!=central && j !=central)
                    {
                        box[i, j] = 'X';
                    }
                }
            }

            for (int l = 0; l < s.Length; l++)
            {
                for (int m = 0; m < s.Length; m++)
                {
                    Console.Write(box[l,m]);
                }
                Console.WriteLine();
            }

        }
    }
}