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

[EX Q]: Sentence: 'a girl sits on a surfboard and smiles'. Find frequency of the letter 'i'
[EX A]: 3

[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 life size teddy bear sitting at a dining table'. Find frequency of the letter 'i'
[EX A]:
6