using System;

public class Program

{

    public static void Main()

    {

        ParseAndPrint("::12");

        ParseAndPrint("10::12");

    }

      private static void ParseAndPrint(string input)

        {

            string[] parts = input.Split(new[] {"::"}, StringSplitOptions.None);

            var left = parts[0];

            var right = parts[1];

​

            Console.WriteLine("L:" + left + " R:" + right);

        }

}