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

[EX Q]: Sentence: 'a double-decker bus covered in children's illustrations driving next to a van'. Find frequency of the letter 'a'
[EX A]: 4

[EX Q]: Sentence: 'a person is riding in a cart pulled by a horse'. Find frequency of the letter 'a'
[EX A]: 4

[EX Q]: Sentence: 'a bright red bus among other busses in a parking lot'. Find frequency of the letter 'e'
[EX A]:
3