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: Carbon atoms are tetravalent, and therefore, can have ____ bonding pairs around each carbon atom.
Example Output: four

Example Input: Infected rodents carry and secrete the virus for about ____ days.
Example Output: seven

Example Input: Pinnipeds have a streamlined, torpedo-shaped body, with all ____ limbs modified into flippers.
Example Output:
four