TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a gray colored pigeon that is perched on a railing outside of a building, with other buildings in the background'. Find frequency of the letter 'e'

SOLUTION: 7

PROBLEM: Sentence: 'a man using a video game controller in a room'. Find frequency of the letter 'n'

SOLUTION: 4

PROBLEM: Sentence: 'the young people are are playing a video game'. Find frequency of the letter 'a'

SOLUTION:
5