TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a person on a sidewalk jumping with an umbrella'. Find frequency of the letter 'a'

SOLUTION: 5

PROBLEM: Sentence: 'the small black and white dog holds onto a frisbee'. Find frequency of the letter 'h'

SOLUTION: 3

PROBLEM: Sentence: 'a person with a cake standing in a room'. Find frequency of the letter 'k'

SOLUTION:
1