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

Example Input: Sentence: 'A cat that is laying down on a bed'. Count the number of verbs in this sentence.
Example Output: 1

Example Input: Sentence: 'A moose is standing out by a river'. Count the number of verbs in this sentence.
Example Output: 1

Example Input: Sentence: 'Three zebra are grazing on grass in an open field'. Count the number of verbs in this sentence.
Example Output:
1