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

[EX Q]: Sentence: 'a couple of buses parked on the side of the street'. Find frequency of the letter 'b'
[EX A]: 1

[EX Q]: Sentence: 'a train sits on a railroad track as a metal awning covers it'. Find frequency of the letter 'l'
[EX A]: 2

[EX Q]: Sentence: 'a kitchen with a black refrigerator, sink window, and a small dining set'. Find frequency of the letter 'g'
[EX A]:
2