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.

Input: Consider Input: Yellow fever begins suddenly after an incubation period of three to ____ days.

Output: five


Input: Consider Input: Natural ytterbium is a mixture of ____ stable isotopes, with seven other unstable isotopes known.

Output: seven


Input: Consider Input: Life begins ____ months earlier at conception when an individual human being comes into existence.


Output: nine