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

[EX Q]: Sentence: 'a parking meter painted green with a sign that describes it as not a parking meter'. Find frequency of the letter 's'
[EX A]: 4

[EX Q]: Sentence: 'a white toilet sitting next to a bathroom sink'. Find frequency of the letter 'b'
[EX A]: 1

[EX Q]: Sentence: 'a man on a surf board rides through the water'. Find frequency of the letter 'n'
[EX A]:
2