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

Sentence: 'a river with a long dragon boat in it and rowers on the boat in sets of two, along with two other people'. Find frequency of the letter 'h'
4

Sentence: 'a number of small boats on a beach near an umbrella'. Find frequency of the letter 's'
2

Sentence: 'a table with a glass of beer next to a bottle'. Find frequency of the letter 's'

2