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

[Q]: Sentence: 'three men in military suits are sitting on a bench,'. Find frequency of the letter 'a'
[A]: 3


[Q]: Sentence: 'a group of cars and house on truck passing in a street'. Find frequency of the letter 'i'
[A]: 2


[Q]: Sentence: 'luggage that has already been unloaded from the baggage carousel and is waiting for the passengers to pick them up'. Find frequency of the letter 'g'
[A]:
8