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

[EX Q]: Sentence: 'a doorway looking into a small bathroom with white toilet'. Find frequency of the letter 'r'
[EX A]: 2

[EX Q]: Sentence: 'a large formal living room with yellow couches and table'. Find frequency of the letter 'v'
[EX A]: 1

[EX Q]: Sentence: 'a group of men standing behind a large flag banner'. Find frequency of the letter 'e'
[EX A]:
4