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

[EX Q]: Sentence: 'group of cars on the road with the sun setting behind it'. Find frequency of the letter 'd'
[EX A]: 2

[EX Q]: Sentence: 'a close up of a bird on the outside window sill'. Find frequency of the letter 'c'
[EX A]: 1

[EX Q]: Sentence: 'batter taking swing at ball during baseball game'. Find frequency of the letter 'n'
[EX A]:
3