In this task, you need to count the number of nouns/verbs in the given sentence.

Example Input: Sentence: 'a small black dog is playing with a green toy'. Count the number of nouns in this sentence.
Example Output: 2

Example Input: Sentence: 'A person is lying on the luggage claim conveyor belt'. Count the number of verbs in this sentence.
Example Output: 1

Example Input: Sentence: 'The front part of a train driving down some tracks'. Count the number of nouns in this sentence.
Example Output:
3