In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.

Input: Consider Input: Fact: optical tools are used for observing materials up close.

Output: materials.


Input: Consider Input: Fact: an animal requires stamina to succeed at physical activities.

Output: animal bear.


Input: Consider Input: Fact: if food is not immediately used by the body for energy then that food will be stored for future use.


Output: body food storage.