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

Ex Input:
Planaria has rudimentary eyes which produce _ images but detect direction.

Ex Output:
no


Ex Input:
Zeolites have basically _ different structural variations.

Ex Output:
three


Ex Input:
Millipedes have _ per body segment and they have lots of body segments.

Ex Output:

four