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

Sentence: 'a young elephant is touching a bigger elephant with its trunk'. Find frequency of the letter 'i'
5

Sentence: 'an image of a cautionary construction sign'. Find frequency of the letter 'a'
5

Sentence: 'a double-decker bus covered in children's illustrations driving next to a van'. Find frequency of the letter 'a'

4