TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a gray airplane with metal petals on the wings takes off from an airport'. Find frequency of the letter 'i'

SOLUTION: 4

PROBLEM: Sentence: 'a couple of boys in a field playing baseball'. Find frequency of the letter 'i'

SOLUTION: 3

PROBLEM: Sentence: 'a plate full of food, with barbeque sauce in the background'. Find frequency of the letter 'e'

SOLUTION:
5