TASK DEFINITION: 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.
PROBLEM: Sentence: 'a boy stares at a pizza with a birthday candle in it'. Count the number of vowels in the given sentence.

SOLUTION: 16

PROBLEM: Sentence: 'an old train next to some empty train tracks'. Count the number of vowels in the given sentence.

SOLUTION: 12

PROBLEM: Sentence: 'crown of people crossing a street in front of a trolly car in the 50's'. Count the number of vowels in the given sentence.

SOLUTION:
18