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

Ex Input:
Ozone is a form of oxygen in which the molecule contains _ atoms instead of two.

Ex Output:
three


Ex Input:
Premolars have one, two, and sometimes _ canals.

Ex Output:
three


Ex Input:
Flexible shapes are also shapes which have _ obvious way of being attacked.

Ex Output:

no