TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a group of cars and house on truck passing in a street'. Find frequency of the letter 'i'

SOLUTION: 2

PROBLEM: Sentence: 'a person is holding a chocolate doughnut with rainbow sprinkles'. Find frequency of the letter 's'

SOLUTION: 4

PROBLEM: Sentence: 'a dog is sitting on a rug in front of a mirror'. Find frequency of the letter 'r'

SOLUTION:
5