public static void Hanoi(int n, string a, string b, string c)
        {
            if (n == 1)
            {
                //move the one dish of a to c
                Console.WriteLine("{0} -> {1}", a, c);
            }
            else if (n > 1)
            {
                //move n-1 dishes of a to b
                Hanoi(n - 1, a, c, b);
                //move the bigest dish of a to c
                Console.WriteLine("{0} -> {1}", a, c);
                //move the n-1 dishes of c to c
                Hanoi(n - 1, b, a, c);
            }
        }