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.

Example Input: Fact: Scientists who find and study fossils are called paleontologists.
Example Output: fossil dinosaur bones.

Example Input: Fact: a mirror is used for reflecting light.
Example Output: light rays.

Example Input: Fact: a battery converts chemical energy into electrical energy.
Example Output:
Electrical energy.