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

[Q]: Sentence: 'a line of people on motorcycles on the road'. Find frequency of the letter 'e'
[A]: 5


[Q]: Sentence: 'a white paper plate with a slice of pizza on it'. Find frequency of the letter 'h'
[A]: 2


[Q]: Sentence: 'a business bus parked near a building'. Find frequency of the letter 'b'
[A]:
3