TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a double parking meter is decorated with a picture of a girl with wings on her feet'. Find frequency of the letter 'r'

SOLUTION: 6

PROBLEM: Sentence: 'three people are gathered around sitting on a park bench'. Find frequency of the letter 'g'

SOLUTION: 2

PROBLEM: Sentence: 'a boy is about to launch himself off the side of a skateboard ramp'. Find frequency of the letter 'e'

SOLUTION:
4