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 table topped with a cupcake on a picture of a cupcake'. Find frequency of the letter 'o'

SOLUTION: 3

PROBLEM: Sentence: 'a group of girls celebrating  as they leave the field'. Find frequency of the letter 'p'

SOLUTION:
1