int a = 0;
            int b = 1;
            int c = 1;
            Console.Write(a + " " + c + " " + b + " ");
            for(int i = 0; i < 20; i++)
            {
                a = b + c;
                b = c;
                c = a;
                Console.Write(b + " ");

            }
            Console.ReadKey();