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

Sentence: 'a man in his car eating a donut'. Find frequency of the letter 'm'
1

Sentence: 'three birds are sitting on a tree in a forest'. Find frequency of the letter 'h'
1

Sentence: 'a keyboard laying on top of a laptop'. Find frequency of the letter 'a'

5