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 group of three dogs laying on a kitchen floor'. Find frequency of the letter 'r'
[EX A]: 3

[EX Q]: Sentence: 'a living room filled with a long yellow couch'. Find frequency of the letter 'f'
[EX A]:
1