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

Ex Input:
All hairs have a life expectancy of _ to six years.

Ex Output:
three


Ex Input:
Economists divide resources into _ basic categories of land, labor, capital, and management.

Ex Output:
four


Ex Input:
Lunar eclipses occur every _ months, on average.

Ex Output:

six