In this task, you need to count the number of times the given letter appears in the given sentence.
--------
Question: Sentence: 'three young people goofing around; one of the guys has a football, the girl has a teddy bear'. Find frequency of the letter 'd'

Answer: 3

Question: Sentence: 'a woman with short, brown hair is looking into a circular mirror and holding a camera up to her cheek'. Find frequency of the letter 'e'

Answer: 4

Question: Sentence: 'a couple of men riding on the back of bikes'. Find frequency of the letter 'b'

Answer:
2