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

Sentence: 'a wedding cake with pink roses on a silver plate'. Find frequency of the letter 'a'
4

Sentence: 'this is a sign in front of a large cathedral'. Find frequency of the letter 'a'
5

Sentence: 'man in a dress shirt and patterned tie posing for a picture'. Find frequency of the letter 'd'

3