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

Example Input: Aquatic adults have prominent red reathery gills, are large, and have _ toes on each foot.
Example Output: four

Example Input: New species are believed to arrive in the Mediterranean at the rate of _ to five annually.
Example Output: four

Example Input: Rainfall can lead to mass movement through _ different mechanisms.
Example Output:
three