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: Spermatogenesis creates ____ sperm of equal size.
Example Output: four

Example Input: Carbon is able to bond with up to ____ other elements.
Example Output: four

Example Input: Green energy comes in ____ basic forms.
Example Output:
two