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

Sentence: 'the small black and white dog holds onto a frisbee'. Find frequency of the letter 'h'
3

Sentence: 'a batter, catcher and umpire waiting for the pitch and a major league baseball game'. Find frequency of the letter 'c'
3

Sentence: 'a man in a business suit talks to a class of young people'. Find frequency of the letter 'f'
1