Definition: 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 was doing research in the library when he heard a man humming and whistling. he was very annoying.
Output:
he