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

Example Input: Bacteria acquire genes conferring resistance in any of _ ways.
Example Output: three

Example Input: Diarrhea is an illness that kills _ and one-half million children per year.
Example Output: three

Example Input: Female dugongs give birth underwater to a single calf at _ to seven year period of time.
Example Output:
three