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

[Q]: Sentence: 'a couple of men standing inside of a liquor store'. Find frequency of the letter 'p'
[A]: 1


[Q]: Sentence: 'the large modern train is on the train track'. Find frequency of the letter 'm'
[A]: 1


[Q]: Sentence: 'a person with long hair riding a surfboard on a wave'. Find frequency of the letter 'g'
[A]:
2