TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'hand holding a white calculator inside a store'. Find frequency of the letter 'o'

SOLUTION: 3

PROBLEM: Sentence: 'a person working at an airport, outside of an airplane'. Find frequency of the letter 'r'

SOLUTION: 5

PROBLEM: Sentence: 'a black dog next to a book titled "cesar's way."'. Find frequency of the letter 'o'

SOLUTION:
4