TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a close up of a train on a track in the dark'. Find frequency of the letter 'a'

SOLUTION: 6

PROBLEM: Sentence: 'slices of orange are arranged on a plate'. Find frequency of the letter 's'

SOLUTION: 2

PROBLEM: Sentence: 'people at a long wooden table in a tavern'. Find frequency of the letter 'n'

SOLUTION:
4