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

[EX Q]: Sentence: 'a giraffe shares a habitat with a zebra, an ostrich, and an okapi'. Find frequency of the letter 'e'
[EX A]: 3

[EX Q]: Sentence: 'a white toilet sitting next to a bathroom sink'. Find frequency of the letter 'b'
[EX A]: 1

[EX Q]: Sentence: 'a room with many beds and rotating fans'. Find frequency of the letter 'r'
[EX A]:
2