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

Sentence: 'a young man with glasses on is taking a big bite'. Find frequency of the letter 's'
4

Sentence: 'a view from a bathroom shows an open door'. Find frequency of the letter 'o'
7

Sentence: 'a couple of people are sitting on a bench'. Find frequency of the letter 'g'

1