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: optical tools are used for observing materials up close.

Ex Output:
materials.


Ex Input:
Fact: Air pollution harms the respiratory and circulatory systems.

Ex Output:
Air pollution caused by.


Ex Input:
Fact: Insects can spread disease and destroy crops.

Ex Output:

Crop destruction.