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

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


[Q]: Sentence: 'a grey hummingbird by fence and tree branches'. Find frequency of the letter 'y'
[A]: 2


[Q]: Sentence: 'four asian guys sitting down and playing a nintendo wii together'. Find frequency of the letter 'r'
[A]:
2