In this task, you will be given a sentence, and you need to identify the set of coreference words. Coreferences are generally a set of words in the text that refer to the same person or thing. Your output set of coreference words must be strictly present in the given input sentence. Do not use any outside knowledge to create the set of coreference words. If there is a 'the' article before the person or thing you should include 'the' as well. Please separate the coreference words by commas in the output.

Example Input: The cook secretly stole the librarian "'s" books to increase his collection .
Example Output: The, cook, his

Example Input: The chief gave the housekeeper a tip because she was helpful .
Example Output: the, housekeeper, she

Example Input: The guard appreciated getting treatment from the nurse because she did a good job .
Example Output:
the, nurse, she