TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a small wrinkley dog wearing a bow tie'. Find frequency of the letter 'e'

SOLUTION: 3

PROBLEM: Sentence: 'food sitting in bowls on table with checked tablecloth'. Find frequency of the letter 't'

SOLUTION: 6

PROBLEM: Sentence: 'a cat sitting on top of a refrigerator'. Find frequency of the letter 'f'

SOLUTION:
2