Answer:
Two: dog and paws
Explanation:
Nouns are words that name a person, animal, thing, place, event, emotion, part of something, etc. whether plural or singular.
In the sentence, "dog" and "paws" are nouns because the first one names an animal, and the second one names one body part of a dog.
The other words of the sentence are not nouns: "The" is an article, "licks" is a verb, "his" is a possessive adjective and "frequently" is an adverb.