TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'three young people goofing around; one of the guys has a football, the girl has a teddy bear'. Find frequency of the letter 'd'

SOLUTION: 3

PROBLEM: Sentence: 'a red fire hydrant opened and spilling water'. Find frequency of the letter 'd'

SOLUTION: 4

PROBLEM: Sentence: 'a person stands on his/her head while a man looks on'. Find frequency of the letter 's'

SOLUTION:
5