TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'there is a zebra that is walking enar a car'. Find frequency of the letter 'r'

SOLUTION: 4

PROBLEM: Sentence: 'a truck with a camper sits parked in some vegetation'. Find frequency of the letter 's'

SOLUTION: 3

PROBLEM: Sentence: 'a sugar doughnut with a bite out of it is held out by two fingers'. Find frequency of the letter 't'

SOLUTION:
7