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

[Q]: Sentence: 'a man flying through the air on top of a skateboard'. Find frequency of the letter 'h'
[A]: 3


[Q]: Sentence: 'a person standing operating a cell phone in a room'. Find frequency of the letter 'n'
[A]: 6


[Q]: Sentence: 'a long bus outside of a red brick building'. Find frequency of the letter 'e'
[A]:
2