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

[Q]: Sentence: 'two people are riding on canoes down a river'. Find frequency of the letter 'e'
[A]: 5


[Q]: Sentence: 'a man on stiltz is standing under a pink umbrella'. Find frequency of the letter 's'
[A]: 3


[Q]: Sentence: 'man sitting on bed in underwear eating pizza'. Find frequency of the letter 's'
[A]:
1