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

[EX Q]: Sentence: 'a close up of a train on a track in the dark'. Find frequency of the letter 'a'
[EX A]: 6

[EX Q]: Sentence: 'a small white plane sitting on top of the ocean'. Find frequency of the letter 'e'
[EX A]: 4

[EX Q]: Sentence: 'a woman in a cowboy hat holding a tray filled with hotdogs'. Find frequency of the letter 'l'
[EX A]:
3