TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'two people under an umbrella while walking down a sidewalk'. Find frequency of the letter 'i'

SOLUTION: 3

PROBLEM: Sentence: 'a kitchen with hanging lights, an island with sink and bar stools, a refrigerator, small pantry door, wooden cabinets and shiny wood floor'. Find frequency of the letter 'n'

SOLUTION: 12

PROBLEM: Sentence: 'a cat walking around a potted plant on a table'. Find frequency of the letter 't'

SOLUTION:
5