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

Sentence: 'people waiting on a train platform in a wooded area'. Find frequency of the letter 'p'
3

Sentence: 'a very big nice looking living room with nice furnishings'. Find frequency of the letter 'e'
3

Sentence: 'stacks of pizzas in pans on a rack waiting to be cooked'. Find frequency of the letter 's'

4