How to I get the input for 3x3 matrix

Console.WriteLine("input:3*3 matrics. number space number space number space enter");
       int[,] input = new int[3, 3];
       for (int i = 0; i < 3; i++)
       {
           for (int j = 0; j < 3; j++)
           {
               var key = Console.ReadKey();
               if (key.Key != ConsoleKey.Spacebar &&  key.Key != ConsoleKey.Enter)
                   input[i, j] = Convert.ToInt32(key.KeyChar.ToString());
               else
                   j--;
               if (key.Key == ConsoleKey.Enter)
                   Console.WriteLine();
           }
       }
       Console.WriteLine();
       Console.WriteLine("output");
       for (int i = 0; i < 3; i++)
       {

           for (int j = 0; j < 3; j++)
           {
               Console.Write(input[i,j] + " ");
           }
           Console.WriteLine( );
       }