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

Example Input: Lactation probably occurs for the first _ months after parturation.
Example Output: two

Example Input: Plants have many white flowers with _ petals, giving the plant a white, flat-topped appearance.
Example Output: four

Example Input: Breakthrough drugs are by definition rare, ranging from one to _ per year worldwide.
Example Output:
three