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

Sentence: 'person wearing all white leaned up against a wall with a yellow sign'. Find frequency of the letter 'a'
8

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

Sentence: 'a boy with a hat on and a bat, glove and ball in his hands'. Find frequency of the letter 'd'

3