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 bed with a mattress that has nothing on it'. Find frequency of the letter 'a'

Answer: 5


Question: Sentence: 'three birds are sitting on a tree in a forest'. Find frequency of the letter 'h'

Answer: 1


Question: Sentence: 'a clock in an old building, above pillars and below a half round stain glass window'. Find frequency of the letter 'o'

Answer:
6