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

[Q]: Sentence: 'a close up of a bird on the outside window sill'. Find frequency of the letter 'c'
[A]: 1


[Q]: Sentence: 'a train going over a bridge with some buildings in the background'. Find frequency of the letter 'd'
[A]: 3


[Q]: Sentence: 'a cat laying underneath a parked car in a driveway'. Find frequency of the letter 'i'
[A]:
3