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

Sentence: 'a dog sitting in the back of a truck flat bed'. Find frequency of the letter 'h'
1

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

Sentence: 'a white fire hydrant posed by the side of a business building'. Find frequency of the letter 'e'

6