You need to answer a given question containing a blank (_). Your answer must be one of the two objects mentioned in the question, for example "trophy" and "suitcase". Your answer must not contain a word that is not present in the question. Please don't use articles (e.g., the, a) before the answer.

Example Input: I was listening to some music while swimming with my phone and headphone but the headphone later stopped working. The _ is waterproof.
Example Output: phone

Example Input: The professor preferred to teach with the books instead of the computers, because the _ were out of date.
Example Output: computers

Example Input: The mailman could not fit the letter into the mail slot because the _ was too thick.
Example Output:
letter