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: Cockroaches have six legs, ____ antennae and some have wings.
Example Output: two

Example Input: Tin has ____ allotropic forms.
Example Output: two

Example Input: Seismologists offer ____ major theories for the occurrence of large, deep earthquakes.
Example Output:
three