In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Input: Consider Input: Phosphates are made of _ phosphorus atom surrounded by four oxygen atoms.

Output: one

Input: Consider Input: Ozone is a gas that consists of _ atoms of oxygen.

Output: three

Input: Consider Input: Chronic pain refers to pain of long duration, typically _ months or greater.
Output: three