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

[Q]: Sentence: 'a person is water skiing and there are birds flying around above them'. Find frequency of the letter 'n'
[A]: 5


[Q]: Sentence: 'a young man with glasses on is taking a big bite'. Find frequency of the letter 's'
[A]: 4


[Q]: Sentence: 'a young lady standing on a  tennis court with a racquet'. Find frequency of the letter 't'
[A]:
5