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

[EX Q]: Sentence: 'a snow filled mountain with a guy with ski's'. Find frequency of the letter 'f'
[EX A]: 1

[EX Q]: Sentence: 'a couple is cutting in to a cake at a wedding'. Find frequency of the letter 'd'
[EX A]: 2

[EX Q]: Sentence: 'a giraffe graze from a tree at a zoo enclosure'. Find frequency of the letter 'c'
[EX A]:
1