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

[EX Q]: Sentence: 'a teenager witting on a futon couch holding gaming controls in both hands'. Find frequency of the letter 'c'
[EX A]: 3

[EX Q]: Sentence: 'a baseball player dropping his bat and starting to run'. Find frequency of the letter 'o'
[EX A]: 2

[EX Q]: Sentence: 'sandwich and salad on a white and blue plate'. Find frequency of the letter 'n'
[EX A]:
4