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: Babies start swimming lessons as young as ____ weeks old.

Output: four


Input: Consider Input: Presidential elections take place every ____ years.

Output: four


Input: Consider Input: Natural chlorine contains ____ isotopes.


Output: two