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

Ex Input:
Boolean operations is a method of combining _ meshes together.

Ex Output:
two


Ex Input:
Flytraps spin when _ creatures can be infected.

Ex Output:
no


Ex Input:
Pinnipeds have a streamlined, torpedo-shaped body, with all _ limbs modified into flippers.

Ex Output:

four