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

Sentence: 'a photo of a small boat on a shore'. Find frequency of the letter 'f'
1

Sentence: 'a giraffe sticking it's tongue out near a window'. Find frequency of the letter 'a'
4

Sentence: 'a birthday cake that has slices missing from it'. Find frequency of the letter 's'

5