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

[EX Q]: Sentence: 'the wooden kitchen has a small child's plastic table in it'. Find frequency of the letter 'n'
[EX A]: 3

[EX Q]: Sentence: 'a young girl skiing down a snowy mountain'. Find frequency of the letter 'l'
[EX A]: 1

[EX Q]: Sentence: 'some water and a black and white clock on a post'. Find frequency of the letter 'o'
[EX A]:
4