Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

Example Input: Most cats have five toes on each front paw, but only ____ toes on each back paw.
Example Output: four

Example Input: Sponges are subdivided into ____ classes.
Example Output: three

Example Input: Diffusion occurs between the capillaries of the ____ blood supplies.
Example Output:
two