Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

Input: Consider Input: Prions are protein molecules which have ____ metastable states.

Output: two


Input: Consider Input: Biological islands are of ____ general types, geographical and ecological.

Output: two


Input: Consider Input: Constipation actually has ____ forms.


Output: two