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

[Q]: Sentence: 'two baseball players high five each other during a game'. Find frequency of the letter 'y'
[A]: 1


[Q]: Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'
[A]: 5


[Q]: Sentence: 'a man helping a boy line up a soccer ball to kick'. Find frequency of the letter 'n'
[A]:
3