int s = Console.Read();
            s++;
            if (s >= 97 && s == 123)  //a=97 z=122
            {
                s = 97;
            }
            else if (s >= 65 && s == 91)  //A=65 Z=90
            {
                s = 65;
            }

            char C = Convert.ToChar(s);

            Console.WriteLine("{0}", C);
            Console.ReadKey();