TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a piece of meat covered in ketchup next to a hamburger on a green plate'. Find frequency of the letter 'g'

SOLUTION: 2

PROBLEM: Sentence: 'a green bus driving in a street filled with heavy traffic'. Find frequency of the letter 'v'

SOLUTION: 2

PROBLEM: Sentence: 'group of people looking at an airplane through a metal fence'. Find frequency of the letter 'e'

SOLUTION:
6