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

[Q]: Sentence: 'a person dressed all in black snowboarding down a slope'. Find frequency of the letter 'e'
[A]: 4


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


[Q]: Sentence: 'a large elephant swimming in a pond full of water'. Find frequency of the letter 'w'
[A]:
2