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: Raindrops produce ____ types of sound underwater.
Example Output: two

Example Input: All ticks have ____ pairs of legs during the immature stage and four pairs as an adult.
Example Output: three

Example Input: Lancelets display all ____ of the vertebrate characteristics throughout their lives.
Example Output:
four