Enter your code here. Read input from STDIN. Print output to STDOUT

Naive implementation. We'll choose correctness over speed here.

This generates a valid delimiter string using a Markov chain-like process.

Convenience function for picking a random value out of a hash.

This randomly invalidates a delimiter string by introducing one of the following errors at a random position: - Delete a delimiter - Add a delimiter -

Some convenience functions for checking that delimiters are of the correct type for eachother. */

Stack methods. */

An empty constructor is used only for creating sentinels, which are useful in some algorithms. This is why a corresponding setValue() is not provided.