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

Sentence: 'a man with a large grey and black beard and glasses and a tie'. Find frequency of the letter 'e'
5

Sentence: 'different sets of luggage in a baggage claim area'. Find frequency of the letter 'r'
2

Sentence: 'a tennis player swinging a racket on a court'. Find frequency of the letter 'i'

3