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

[Q]: Sentence: 'a person trying to flip a skateboard in a garage'. Find frequency of the letter 'a'
[A]: 7

[Q]: Sentence: 'some food on plates next to each other on a table'. Find frequency of the letter 'e'
[A]: 6

[Q]: Sentence: 'a young girl sitting at a table eating a doughnut'. Find frequency of the letter 'y'
[A]:
1