Cycle through the following operations one at a time until no further operations can be performed:

1. If the string prefix is 'ca', replace it with 'bb' and append 'c' to the end.
2. If the string length is greater than 15, remove the middle character.
3. If the string ends with 'ba', replace it with 'ab'.
4. If the string suffix is 'bb', delete the last two characters.
5. If the string contains an even number of 'b's (and at least one 'b'), append 'ab' at the end.
6. If the string prefix is 'bc', delete the first two characters and append 'aa' to the end.

For the string "ababcbbbbbbabaccac", what is the final string after performing all operations?

Provide your answer as a string in the following format:

<<< "some_final_string" >>>
