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 white and blue plate topped with meat and a salad'. Find frequency of the letter 'u'

SOLUTION: 1

PROBLEM: Sentence: 'a swinging half-door opens in to a small cabin'. Find frequency of the letter 'a'

SOLUTION:
5