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

Example Input: Plants grow to _ feet tall with feathery, smoky purple foliage.
Example Output: four

Example Input: Trees can also be air layered but air layering usually takes four to _ months to be successful.
Example Output: six

Example Input: Young birds stay in the nest three to _ weeks.
Example Output:
four