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: cutting down trees has a negative impact on an ecosystem.

Ex Output:
cutting down trees.


Ex Input:
Fact: plucking a string can cause that string to vibrate.

Ex Output:
guitars strings sound.


Ex Input:
Fact: Mutations may change the structure of a chromosome or just change a single nucleotide.

Ex Output:

Mutations cause.