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: Couples spend ____ billion dollars a year on infertility treatments.
Example Output: two

Example Input: Neurofibromatosis appears in ____ forms.
Example Output: two

Example Input: Oestrus lasts ____ days, and mating is unusually brief.
Example Output:
five