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: 'two zebras standing around while a third zebra drinks from a pond'. Find frequency of the letter 's'

Answer: 3

Question: Sentence: 'a little boy that has a toothbrush in his mouth'. Find frequency of the letter 'r'

Answer: 1

Question: Sentence: 'a bunch of chairs sitting in a room, with a fan behind them'. Find frequency of the letter 's'

Answer:
2