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

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

[EX Q]: Sentence: 'three birds are sitting on a tree in a forest'. Find frequency of the letter 'h'
[EX A]: 1

[EX Q]: Sentence: 'a man with beard taking a photograph with a cellphone'. Find frequency of the letter 'a'
[EX A]:
7