In this task, you need to count the number of times the given letter appears in the given sentence.

Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'
4

Sentence: 'a woman in a messy kitchen with a child'. Find frequency of the letter 'a'
4

Sentence: 'a tower clock sits alone in a light blue sky'. Find frequency of the letter 'e'

3