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

[Q]: Sentence: 'a little boy sitting on a bed in a bedroom'. Find frequency of the letter 'e'
[A]: 3


[Q]: Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'
[A]: 5


[Q]: Sentence: 'a red stop sign sitting on the side of a road'. Find frequency of the letter 'i'
[A]:
4