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

Sentence: 'an commercial airline airplane flies above the clouds'. Find frequency of the letter 'n'
3

Sentence: 'an old boat on a beach near a large body of water'. Find frequency of the letter 'a'
8

Sentence: 'hot dogs in buns sit on a table along with beverages'. Find frequency of the letter 't'

4