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

[Q]: Sentence: 'a person riding a surfboard in the middle of a wave'. Find frequency of the letter 'o'
[A]: 3


[Q]: Sentence: 'a group of men standing around a table cutting a cake'. Find frequency of the letter 'g'
[A]: 3


[Q]: Sentence: 'a small wrinkley dog wearing a bow tie'. Find frequency of the letter 'e'
[A]:
3