TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a person riding a skate board on a city street'. Find frequency of the letter 'a'

SOLUTION: 5

PROBLEM: Sentence: 'a sailboat is floating near the rocky shore of a beach'. Find frequency of the letter 'o'

SOLUTION: 5

PROBLEM: Sentence: 'a man is sitting on a bench while wearing an native american headdress'. Find frequency of the letter 'a'

SOLUTION:
9