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: Biennials require portions of ____ growing seasons to reproduce.
Example Output: two

Example Input: Sexual maturity is reached at ____ years, and females calve every other year.
Example Output: four

Example Input: Outer shells can hold more electrons but are considered stable when they contain ____ electrons.
Example Output:
eight