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: Elephants have five toes on the fore feet and ____ on the hind feet.
Example Output: four

Example Input: Pyrimidines contain ____ ring and purines contain two rings.
Example Output: one

Example Input: Most children usually stop having multiple ear infections by the time they are about ____ years old.
Example Output:
four