TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a street at night with trees and streetlights on'. Find frequency of the letter 't'

SOLUTION: 9

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

SOLUTION: 3

PROBLEM: Sentence: 'a train coming around a curve by a sidewalk'. Find frequency of the letter 'c'

SOLUTION:
2