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

Example Input: Corms are undifferentiated, uniform, and contain _ rings when cut apart.
Example Output: no

Example Input: Willow flycatchers have a lifespan of _ to four years.
Example Output: three

Example Input: Most walkers do walk at least half an hour at a time, but fewer walk _ or more times a week.
Example Output:
four