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

[Q]: Sentence: 'a man with a skateboard that is in the street'. Find frequency of the letter 'o'
[A]: 1


[Q]: Sentence: 'a player swings his bat at a baseball game'. Find frequency of the letter 'p'
[A]: 1


[Q]: Sentence: 'a couple of boats floating on top of a body of water'. Find frequency of the letter 'a'
[A]:
5