In this task, you need to count the number of vowels (letters 'a', 'e', 'i', 'o', 'u') / consonants (all letters other than vowels) in the given sentence.

Example Input: Sentence: 'two people are standing next to a giraffe'. Count the number of vowels in the given sentence.
Example Output: 14

Example Input: Sentence: 'this old washed out photo shows a couple of people with several horses in front of a silo and barn'. Count the number of vowels in the given sentence.
Example Output: 31

Example Input: Sentence: 'a vegetable pizza that has been sliced into pieces'. Count the number of vowels in the given sentence.
Example Output:
18