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.

Ex Input:
The librarian helped the CEO to find the book because he asked to .

Ex Output:
the, CEO, he


Ex Input:
The clerk misled the supervisor so she got fired .

Ex Output:
The, clerk, she


Ex Input:
The supervisor provided the writer with new tools but she did not appreciate it .

Ex Output:

the, writer, she