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

[EX Q]: Sentence: 'a boy that is sitting at a table with pizza'. Find frequency of the letter 's'
[EX A]: 2

[EX Q]: Sentence: 'a photo of a toilet which is not clean'. Find frequency of the letter 'w'
[EX A]: 1

[EX Q]: Sentence: 'a person cutting into a chocolate cake with syrup on it'. Find frequency of the letter 'o'
[EX A]:
5