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

Example Input: Sentence: 'One person tossing a frisbee to another person in front of some trees'. Count the number of verbs in this sentence.
Example Output: 1

Example Input: Sentence: 'A very old style fire truck at the station'. Count the number of verbs in this sentence.
Example Output: 0

Example Input: Sentence: 'Two people skiing down a snow covered slop next to a banner'. Count the number of verbs in this sentence.
Example Output:
2