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.

Ex Input:
Fact: Roundworms make up the phylum Nematoda.

Ex Output:
Nematoda.


Ex Input:
Fact: Plants use cellulose for their cell walls.

Ex Output:
cell walls.


Ex Input:
Fact: Lions live in social groups called prides.

Ex Output:

Lion.