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

Example Input: Cholesterol comes from _ sources.
Example Output: two

Example Input: Echocardiography demonstrates in clear, graphic fashion the _ cardiac chambers and four valves.
Example Output: four

Example Input: Platelets are very delicate, enable cuts to heal and only last for _ days.
Example Output:
five