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

Sentence: 'a man flying through the air on top of a skateboard'. Find frequency of the letter 'r'
3

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

Sentence: 'bowls of food sitting side by side on a tabel'. Find frequency of the letter 'd'
3