TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a parking meter painted green with a sign that describes it as not a parking meter'. Find frequency of the letter 's'

SOLUTION: 4

PROBLEM: Sentence: 'a bed with a dog laying on it next to two laptop computers'. Find frequency of the letter 'n'

SOLUTION: 3

PROBLEM: Sentence: 'a microwave oven with a yellow note on the door'. Find frequency of the letter 'w'

SOLUTION:
3