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

Ex Input:
Whales have only _ enemies-man and the killer whale.

Ex Output:
two

Ex Input:
Germs have _ means of locomotion execpt to attach themselves to particles of dust.

Ex Output:
no

Ex Input:
Cubs start to walk at _ months of age.

Ex Output:
four