TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'man in red shirt with black suitcase standing outside of building'. Find frequency of the letter 'i'

SOLUTION: 8

PROBLEM: Sentence: 'two elephants facing each other touching trunks in an enclosure'. Find frequency of the letter 'f'

SOLUTION: 1

PROBLEM: Sentence: 'a horse in the back of a truck'. Find frequency of the letter 'r'

SOLUTION:
2