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 group of three dogs laying on a kitchen floor'. Find frequency of the letter 'r'

Answer: 3


Question: Sentence: 'a train is sitting at a train station'. Find frequency of the letter 'r'

Answer: 2


Question: Sentence: 'person grating cheese on top of small pizza'. Find frequency of the letter 'r'

Answer:
2