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

Sentence: 'man in red shirt with black suitcase standing outside of building'. Find frequency of the letter 'i'
8

Sentence: 'a person is riding in a cart pulled by a horse'. Find frequency of the letter 'a'
4

Sentence: 'a pile of women's makeup, some cash, and other objects'. Find frequency of the letter 'i'

1