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: 'people playing wii bowling in a modern library'. Find frequency of the letter 'o'

SOLUTION: 3

PROBLEM: Sentence: 'a man on cellphone standing in doorway next to shelves'. Find frequency of the letter 'o'

SOLUTION:
5