TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a baseball player dropping his bat and starting to run'. Find frequency of the letter 'o'

SOLUTION: 2

PROBLEM: Sentence: 'a girl playing with a frisbee while people watch'. Find frequency of the letter 'e'

SOLUTION: 5

PROBLEM: Sentence: 'a man holding a tennis racket and ball standing next to a toddler on a court'. Find frequency of the letter 'n'

SOLUTION:
9