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

[Q]: Sentence: 'a guy riding a bike close to a car in the street'. Find frequency of the letter 'i'
[A]: 4


[Q]: Sentence: 'a man paddle boarding by a boat dock in a city'. Find frequency of the letter 'o'
[A]: 3


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