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 log in the water with three birds perched on it'. Find frequency of the letter 'r'

Answer: 4


Question: Sentence: 'a red and white train passing a train station'. Find frequency of the letter 'a'

Answer: 7


Question: Sentence: 'an image of a man sitting in the grass next to a dog'. Find frequency of the letter 'i'

Answer:
4