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

[Q]: Sentence: 'a herd of giraffe walking across a field'. Find frequency of the letter 'k'
[A]: 1

[Q]: Sentence: 'a couple of men sitting next to each other under an umbrella'. Find frequency of the letter 'n'
[A]: 5

[Q]: Sentence: 'an ipod is charging on a desk with the ear buds laying close by'. Find frequency of the letter 'e'
[A]:
4