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: a seismometer is used to measure the strength or magnitude of an earthquake.
Example Output: earthquake cause.

Example Input: Fact: Most carcinogens cause cancer by producing mutations in DNA.
Example Output: cancer can cause death.

Example Input: Fact: Ice ages buried the planet in snow and ice for millions of years at a time.
Example Output:
ice age.