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: sonar is used to find the location of an object.
Example Output: Location of an object.

Example Input: Fact: when a body of water receives more water than it can hold , a flood occurs.
Example Output: body of water river.

Example Input: Fact: if the amount of available food and water decreases in an environment then animals may leave that environment to find food and water.
Example Output:
animals bears.