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

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

Sentence: 'a young girl is brushing her teeth in this dated photo'. Find frequency of the letter 't'
5

Sentence: 'a photo of a toilet with a mirror reflecting'. Find frequency of the letter 'i'

4