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

[Q]: Sentence: 'a car accident has slowed traffic as a clean up crew works'. Find frequency of the letter 'f'
[A]: 2


[Q]: Sentence: 'two computers and a laptop set up on a desk'. Find frequency of the letter 'r'
[A]: 1


[Q]: Sentence: 'a plane flies through the clouds on a rainy day'. Find frequency of the letter 't'
[A]:
2