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: fossils are formed when layers of sediment cover the remains of organisms over time.
Example Output: fish organisms.

Example Input: Fact: nuclear reactions in stars causes stars to produce light.
Example Output: light contains photons.

Example Input: Fact: insulated material can be used for keeping warm.
Example Output:
insulate.