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 laborer told the teacher that she needed to speak louder in class .
Example Output: the, teacher, she

Example Input: The developer refused to take a book from the librarian because he liked the internet better than books .
Example Output: The, developer, he

Example Input: The mover said thank you to the housekeeper because he is grateful .
Example Output:
The, mover, he

