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

[Q]: Sentence: 'a bird in a tree looking up at branches'. Find frequency of the letter 'e'
[A]: 3


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


[Q]: Sentence: 'two beds turned down with white sheets and a bright light between them'. Find frequency of the letter 's'
[A]:
3