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

Sentence: 'there is a sandwich with a lot of meat cut in half'. Find frequency of the letter 'a'
5

Sentence: 'a man on stiltz is standing under a pink umbrella'. Find frequency of the letter 's'
3

Sentence: 'flat bread pizza slices piled on top of each other'. Find frequency of the letter 't'

3