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

[EX Q]: Sentence: 'small airplane in the process of taking off'. Find frequency of the letter 'e'
[EX A]: 3

[EX Q]: Sentence: 'a closeup view of a bathroom sink, that is very modern'. Find frequency of the letter 'e'
[EX A]: 4

[EX Q]: Sentence: 'a double exposed photo of a person standing with an umbrella'. Find frequency of the letter 'n'
[EX A]:
4