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

[EX Q]: Sentence: 'a man standing on a surf board in the ocean'. Find frequency of the letter 'f'
[EX A]: 1

[EX Q]: Sentence: 'the street sign is next to a curved road'. Find frequency of the letter 's'
[EX A]: 3

[EX Q]: Sentence: 'a person skiing on a bench in the snow'. Find frequency of the letter 'e'
[EX A]:
3