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.

Ex Input:
Some airports have ____ parallel runways.

Ex Output:
two


Ex Input:
Avian kidneys have ____ kinds of nephrons.

Ex Output:
two


Ex Input:
Natural selenium contains ____ stable iso- topes.

Ex Output:

six