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

Input: Consider Input: Polymorphism occurs in all species and the mandibles bear _ teeth.

Output: four


Input: Consider Input: Flatworms exhibit _ forms of life styles, free-living and parasitic.

Output: two


Input: Consider Input: Health prevails when the _ humors of the body are in balance, disease when there is imbalance.


Output: four