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.

Input: Consider Input: Fact: fog is formed by water vapor condensing in the air.

Output: fog is formed.


Input: Consider Input: Fact: if a tree falls then sunlight becomes available to the surrounding plants.

Output: large shade trees.


Input: Consider Input: Fact: measuring the hardness of minerals requires scratching those materials.


Output: hardness minerals.