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

[EX Q]: Sentence: 'a person is water skiing and there are birds flying around above them'. Find frequency of the letter 'n'
[EX A]: 5

[EX Q]: Sentence: 'a microwave oven with a yellow note on the door'. Find frequency of the letter 'w'
[EX A]: 3

[EX Q]: Sentence: 'a tennis player swinging a racket on a court'. Find frequency of the letter 'i'
[EX A]:
3