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 is riding in a cart pulled by a horse'. Find frequency of the letter 'a'

SOLUTION: 4

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

SOLUTION: 3

PROBLEM: Sentence: 'a pair of cattle yoked to a covered cart'. Find frequency of the letter 'o'

SOLUTION:
4