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 person working at an airport, outside of an airplane'. Find frequency of the letter 'r'

Answer: 5


Question: Sentence: 'salad and vegetables with me on top of plate'. Find frequency of the letter 'o'

Answer: 3


Question: Sentence: 'a dog sitting in a kennel on a bed with its mouth opened'. Find frequency of the letter 't'

Answer:
5