TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a notebook and pen are left on a park bench'. Find frequency of the letter 'e'

SOLUTION: 5

PROBLEM: Sentence: 'an elephant with broken tusks stands in front of a hill and boulders'. Find frequency of the letter 'n'

SOLUTION: 7

PROBLEM: Sentence: 'a roof and window view has an attached clock'. Find frequency of the letter 'e'

SOLUTION:
2