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: Prokaryotes are single-celled organisms that lack a nucleus.

Ex Output:
Prokaryotes.


Ex Input:
Fact: Adult echinoderms have radial symmetry.

Ex Output:
echinoderm is starfish.


Ex Input:
Fact: electrical current running through a wire causes that wire to heat up.

Ex Output:

current electric heat.