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: a sandbar is formed by water moving sediment downstream.

Ex Output:
sandbar habitat.


Ex Input:
Fact: Digestion is the process of breaking down food into components the body can absorb.

Ex Output:
Digestion.


Ex Input:
Fact: erosion causes a river to become deeper and wider.

Ex Output:

erosion alters.