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

[Q]: Sentence: 'a person trying to flip a skateboard in a garage'. Find frequency of the letter 'a'
[A]: 7


[Q]: Sentence: 'a dog sitting in the back of a truck flat bed'. Find frequency of the letter 'h'
[A]: 1


[Q]: Sentence: 'a person on top of a street light with a video camera'. Find frequency of the letter 'h'
[A]:
2