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

Sentence: 'a large cooked pizza on a dining table'. Find frequency of the letter 'n'
3

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

Sentence: 'a stop sign that someone wrote war under stop on'. Find frequency of the letter 'm'

1