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

[EX Q]: Sentence: 'a jet that is flying in the sky with a banner behind it'. Find frequency of the letter 'r'
[EX A]: 1

[EX Q]: Sentence: 'two elephants walking on cement next to wall'. Find frequency of the letter 'n'
[EX A]: 5

[EX Q]: Sentence: 'person standing in the kitchen with two dogs at their feet'. Find frequency of the letter 'a'
[EX A]:
2