TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a passenger train that is going over a bridge'. Find frequency of the letter 't'

SOLUTION: 3

PROBLEM: Sentence: 'a small wrinkley dog wearing a bow tie'. Find frequency of the letter 'e'

SOLUTION: 3

PROBLEM: Sentence: 'a woman on the tennis court holds a racket, while other people stand along the fence'. Find frequency of the letter 'c'

SOLUTION:
3