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: 'a red and white train passing a train station'. Find frequency of the letter 'a'
7

Sentence: 'a man laying on a chair with a woman while holding a banana'. Find frequency of the letter 'l'

3