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: living things all require energy for survival.
Example Output: energy food.

Example Input: Fact: when a cooler object touches a warmer object , thermal conduction occurs.
Example Output: conduction heat.

Example Input: Fact: adding salt to a solid decreases the freezing point of that solid.
Example Output:
adding salt solid freezing.