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 stiltz is standing under a pink umbrella'. Find frequency of the letter 's'

SOLUTION: 3

PROBLEM: Sentence: 'a fluffy white car looking in a mirror'. Find frequency of the letter 'k'

SOLUTION: 1

PROBLEM: Sentence: 'a bedroom with a bed that has white covers'. Find frequency of the letter 'd'

SOLUTION:
2