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.

Example Input: Lung disease is America's number ____ killer, responsible for one in seven deaths.
Example Output: three

Example Input: All birds have ____ legs with four toes each.
Example Output: two

Example Input: Equations are statements which say that ____ quantities are equal.
Example Output:
two