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

[EX Q]: Sentence: 'the counter of a doctor's office, including a laptop, cotton swabs, and tongue depressors'. Find frequency of the letter 'g'
[EX A]: 2

[EX Q]: Sentence: 'two men sitting quietly on a park bench'. Find frequency of the letter 'a'
[EX A]: 2

[EX Q]: Sentence: 'a man hiking up a hill with skis in his hands'. Find frequency of the letter 'n'
[EX A]:
4