TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a dilapidated bench in a park under a tree'. Find frequency of the letter 'p'

SOLUTION: 2

PROBLEM: Sentence: 'a man standing on a tennis court holding a racquet'. Find frequency of the letter 's'

SOLUTION: 2

PROBLEM: Sentence: 'an animal standing on train tracks at a passenger stop'. Find frequency of the letter 'n'

SOLUTION:
7