TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a young man riding a skateboard near a forest'. Find frequency of the letter 'd'

SOLUTION: 2

PROBLEM: Sentence: 'a bunch of cows that are in the field'. Find frequency of the letter 'a'

SOLUTION: 3

PROBLEM: Sentence: 'a baseball player throws out a fast pitch'. Find frequency of the letter 't'

SOLUTION:
4