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

[Q]: Sentence: 'old double decker bus parked in a lot'. Find frequency of the letter 't'
[A]: 1


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


[Q]: Sentence: 'a large ship in a body of water'. Find frequency of the letter 'a'
[A]:
4