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

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

Sentence: 'a crowd of people skiing and enjoying the snow'. Find frequency of the letter 'o'
5

Sentence: 'a rat standing on a desk next to a computer and mouse'. Find frequency of the letter 'r'

2