TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a closeup view of a bathroom sink, that is very modern'. Find frequency of the letter 'e'

SOLUTION: 4

PROBLEM: Sentence: 'a guy surfs a wave with his surfboard'. Find frequency of the letter 's'

SOLUTION: 4

PROBLEM: Sentence: 'a person on a snowboard weaves down a mountain slope'. Find frequency of the letter 'o'

SOLUTION:
7