Below, you can find another hint for the Challenge.
You should only get here after reading, digesting, and applying the .
Single characters cannot be used as markers. Why would multiple character sequences work? Consider a two-character sequence starting with some character c. How do we now express that character c? Well, using another two-character code. There are plenty of two-character sequences.
A choice that is often made, is to use cc as code for c. And other combinations cx can be used for other purposes.
Character c is then called an escape character, because it indicates that the next characters should be treated in a special way.
Can you apply this idea?
Try your program in the machine, and see if you can extend it to an improved solution.
It is your turn ...
If you tried this hint, or do not see how it helps, then you are ready for the .