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

[EX Q]: Sentence: 'a dog sitting in the back of a truck flat bed'. Find frequency of the letter 'h'
[EX A]: 1

[EX Q]: Sentence: 'a jet flying through the clear blue sky'. Find frequency of the letter 'g'
[EX A]: 2

[EX Q]: Sentence: 'boats sailing on a large body of water under a cloudy blue sky'. Find frequency of the letter 'e'
[EX A]:
4