TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a man on a skateboard going down a ramp while people are watching'. Find frequency of the letter 'w'

SOLUTION: 3

PROBLEM: Sentence: 'two elephants walking on cement next to wall'. Find frequency of the letter 'n'

SOLUTION: 5

PROBLEM: Sentence: 'children are gathered around cakes and cupcakes at a birthday party'. Find frequency of the letter 'a'

SOLUTION:
10