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

[EX Q]: Sentence: 'the large modern train is on the train track'. Find frequency of the letter 'm'
[EX A]: 1

[EX Q]: Sentence: 'a double decker transit bus parks by a blue on the side of the street in front of a brick building in the city'. Find frequency of the letter 't'
[EX A]: 9

[EX Q]: Sentence: 'a bunch of doughnuts that are on a table'. Find frequency of the letter 'u'
[EX A]:
3