TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'an area that has surrounded by a metal fence'. Find frequency of the letter 'o'

SOLUTION: 1

PROBLEM: Sentence: 'a man flying through the air on top of a skateboard'. Find frequency of the letter 'h'

SOLUTION: 3

PROBLEM: Sentence: 'a tooth brush in a glass holder next to a bathroom sink'. Find frequency of the letter 'n'

SOLUTION:
3