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

Sentence: 'a man is taking a picture of a man and woman'. Find frequency of the letter 'a'
8

Sentence: 'a person is holding a chocolate doughnut with rainbow sprinkles'. Find frequency of the letter 's'
4

Sentence: 'the back of a person's head with elephants in the background'. Find frequency of the letter 'w'

1