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

[EX Q]: Sentence: 'a guy riding a bike close to a car in the street'. Find frequency of the letter 'i'
[EX A]: 4

[EX Q]: Sentence: 'a man pushing a cart full of bananas'. Find frequency of the letter 'u'
[EX A]: 2

[EX Q]: Sentence: 'a train car with graphittie on it is stopped in the station'. Find frequency of the letter 'i'
[EX A]:
8