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: 'a young woman dressed in green and black operating a remote control'. Find frequency of the letter 'r'
[A]: 5


[Q]: Sentence: 'a black traffic light on a white street post'. Find frequency of the letter 'h'
[A]:
2