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

Ex Input:
Most insects have _ wings, but dipterans have only two.

Ex Output:
four


Ex Input:
Mountain sheep have _ sharp teeth at the front of the mouth.

Ex Output:
eight


Ex Input:
Urban sprawl reduces farmland at the rate of one acre for each _ births.

Ex Output:

five