TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a man sitting inside a green military truck talking to someone'. Find frequency of the letter 'i'

SOLUTION: 7

PROBLEM: Sentence: 'a giraffe shares a habitat with a zebra, an ostrich, and an okapi'. Find frequency of the letter 'e'

SOLUTION: 3

PROBLEM: Sentence: 'two men stand in a living room playing a video game'. Find frequency of the letter 'o'

SOLUTION:
4