Instructions: Indicate all the pronouns (they, them, you, he, his, her, you, it, etc.) present in the given sentence. If there are multiple such pronouns in a sentence, then list them in the order of their first appearance in the given sentence. If a pronoun appears multiple times in a sentence, list it only once.
Input: john couldn't see the stage with billy in front of him because he is so short.
Output:
him, he