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.

Input: Consider Input: The janitor cleaned the librarian "'s" room and she was grateful .

Output: the, librarian, she


Input: Consider Input: The laborer told the baker that he needed a cake by tomorrow .

Output: The, laborer, he


Input: Consider Input: The lawyer needed the librarian to find a book because he does not know how a library works .


Output: The, lawyer, he