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

[Q]: Sentence: 'a black animal in dirt area below trees and rocks'. Find frequency of the letter 'n'
[A]: 3

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

[Q]: Sentence: 'man and woman cutting a white wedding cake'. Find frequency of the letter 'n'
[A]:
5