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: Viruses are not cells.
Example Output: Viruses.

Example Input: Fact: burning wood is used to produce heat.
Example Output: burning wood trees.

Example Input: Fact: Bees are naturalized on every continent except Antarctica.
Example Output:
Antarctica.