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

Sentence: 'cooked fish and green broccoli share a single white plate'. Find frequency of the letter 'c'
3

Sentence: 'a man working on a small laptop on a wooden table'. Find frequency of the letter 'l'
4

Sentence: 'a room filled with furniture and a tv'. Find frequency of the letter 'a'
3