TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a golden haired dog looking out of an open window'. Find frequency of the letter 'd'

SOLUTION: 4

PROBLEM: Sentence: 'a couple of people that are on a baseball field'. Find frequency of the letter 'c'

SOLUTION: 1

PROBLEM: Sentence: 'a stoplight with a sign on the top of them'. Find frequency of the letter 'e'

SOLUTION:
2