TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a crowd of people skiing and enjoying the snow'. Find frequency of the letter 'o'

SOLUTION: 5

PROBLEM: Sentence: 'a small boat and a large boat on a river near a city'. Find frequency of the letter 'a'

SOLUTION: 10

PROBLEM: Sentence: 'a person flying a kite in the sky'. Find frequency of the letter 'n'

SOLUTION:
3