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

Sentence: 'two men are playing a video game as another sits watching'. Find frequency of the letter 'a'
7

Sentence: 'small black bird with red on its head standing on a tree branch'. Find frequency of the letter 'b'
3

Sentence: 'a living room of a cabin-style house features furniture and some antique items'. Find frequency of the letter 't'
5