In this task, you need to count the number of times the given letter appears in the given sentence.

Sentence: 'a truck with a camper sits parked in some vegetation'. Find frequency of the letter 's'
3

Sentence: 'a little dog on a table while a dog groomer cuts its fur'. Find frequency of the letter 'r'
3

Sentence: 'a couple of people that have some wii remotes in hand'. Find frequency of the letter 'i'

3