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: Ligand seeks ____ receptors into binding and mutual phosporylation.

Output: two


Input: Consider Input: Avian kidneys have ____ kinds of nephrons.

Output: two


Input: Consider Input: Respiratory therapists complete ____ to four years of education.


Output: two