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: a flower 's purpose is to produce seeds.
Example Output: animals seeds.

Example Input: Fact: Some parasites live on the surface of their host.
Example Output: Surface parasite.

Example Input: Fact: Ozone depletion results in higher levels of UV radiation reaching Earth.
Example Output:
Ozone depletion.