TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'small airplane in the process of taking off'. Find frequency of the letter 'e'

SOLUTION: 3

PROBLEM: Sentence: 'a young girl skiing down a snowy mountain'. Find frequency of the letter 'l'

SOLUTION: 1

PROBLEM: Sentence: 'a small bird perched on top of a glass of water'. Find frequency of the letter 'p'

SOLUTION:
2