problem in console application

Question

My code :

            sbyte b;
            string x;
            sbyte a;
            a = 5;
            x = Console.ReadLine();
            b = Convert.ToSByte(Console.ReadLine());
            b += a;
            Console.WriteLine(" my number (0) " , b );
            Console.ReadKey();

My result :

abd
5
  my number (0)