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

Sentence: 'a boy catching a frisbee while standing ins bunch of leaves'. Find frequency of the letter 'a'
5

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'
3

Sentence: 'a man makes some cock tales at a desk'. Find frequency of the letter 'k'

3