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

[Q]: Sentence: 'a small boat travels on the water next to the shore'. Find frequency of the letter 'a'
[A]: 5


[Q]: Sentence: 'men are riding on motorcycles with a man riding in their carriers'. Find frequency of the letter 'r'
[A]: 8


[Q]: Sentence: 'group of people standing around a brown and green cake on a table'. Find frequency of the letter 's'
[A]:
1