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: Bone is less flexible than cartilage but stronger.
Example Output: bone cartilage.

Example Input: Fact: friction causes the temperature of an object to increase.
Example Output: friction movement.

Example Input: Fact: using cell phones can cause people to become distracted.
Example Output:
cell phone communicate.