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: 'girls posing of a picture one holding a tennis racket the other wearing a crown'. Find frequency of the letter 'g'

Answer: 4

Question: Sentence: 'the two dogs are playing in the pen together'. Find frequency of the letter 'o'

Answer: 3

Question: Sentence: 'some police officers on some very pretty horses by some buildings'. Find frequency of the letter 'm'

Answer:
3