1

 static void Main(string[] args)
        {
            String x;
            String y;

            x = Console.ReadLine();
            y = Console.ReadLine();

            if (x.Length == y.Length) { Console.WriteLine("OK"); }

            if (x.Length < y.Length)
            {
                while (x.Length != y.Length)
                {
                    x = "0" + x;
                }
                Console.WriteLine(x);
            }

            if (x.Length > y.Length)
            {
                while (x.Length != y.Length)
                {
                    y = "0" + y;
                }
                Console.WriteLine(y);
            }
        }