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

[Q]: Sentence: 'a bathroom with a sink, counter top, and mirror is shown'. Find frequency of the letter 'i'
[A]: 4


[Q]: Sentence: 'a scene at night; a plane alone on a runway with lit-up city buildings on the horizon'. Find frequency of the letter 'w'
[A]: 2


[Q]: Sentence: 'the image shows a book digitally modified onto a tennis racket'. Find frequency of the letter 'a'
[A]:
5