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 tennis players on a tennis court'. Find frequency of the letter 'o'

Answer: 4


Question: Sentence: 'a little dog on a table while a dog groomer cuts its fur'. Find frequency of the letter 'r'

Answer: 3


Question: Sentence: 'a man in a blue shirt swings a tennis racket'. Find frequency of the letter 's'

Answer:
4