In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Example Input: Copper has _ stable isotopes.
Example Output: two

Example Input: Asbestos is the name applied to _ naturally occurring minerals that are mined from the earth.
Example Output: six

Example Input: Many diseases require the tick to be attached for _ or more hours to transmit disease.
Example Output:
six