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

Sentence: 'a toasted sub sandwich is next to a salad'. Find frequency of the letter 'a'
6

Sentence: 'a variety of a different type of vegetables'. Find frequency of the letter 't'
4

Sentence: 'a close up shot of a computer with some accessories'. Find frequency of the letter 'a'

3