In this task, you need to count the number of times the given letter appears in the given sentence.
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Question: Sentence: 'a bunch of broken down trains sit in a yard'. Find frequency of the letter 'n'

Answer: 5


Question: Sentence: 'there is a sandwich with a lot of meat cut in half'. Find frequency of the letter 'a'

Answer: 5


Question: Sentence: 'man in air skateboarding on street with building'. Find frequency of the letter 't'

Answer:
4