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

[EX Q]: Sentence: 'a photo of a small boat on a shore'. Find frequency of the letter 'f'
[EX A]: 1

[EX Q]: Sentence: 'a crowd of people standing in front of a green train'. Find frequency of the letter 'g'
[EX A]: 2

[EX Q]: Sentence: 'a kite is flying in the air over a sandy beach as a person windsurfs below'. Find frequency of the letter 'b'
[EX A]:
2