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 standing operating a cell phone in a room'. Find frequency of the letter 'n'

SOLUTION: 6

PROBLEM: Sentence: 'old double decker bus parked in a lot'. Find frequency of the letter 't'

SOLUTION: 1

PROBLEM: Sentence: 'some people playing with some kites on top of a hill'. Find frequency of the letter 'p'

SOLUTION:
4