TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'man in a sleeping bag on the floor using a laptop computer'. Find frequency of the letter 'i'

SOLUTION: 3

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 baseball player and a pitcher preparing for the pitch'. Find frequency of the letter 't'

SOLUTION:
3