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

Sentence: 'a large grass pasture land with sheep grazing on grass'. Find frequency of the letter 'a'
7

Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'
4

Sentence: 'two pizzas on a table and one is being eaten'. Find frequency of the letter 'z'

2