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 man and a woman are walking down the street with an umbrella over their heads'. Find frequency of the letter 'w'

Answer: 4


Question: Sentence: 'two people under an umbrella while walking down a sidewalk'. Find frequency of the letter 'i'

Answer: 3


Question: Sentence: 'a man standing in front of a restaurant next to a parking meter'. Find frequency of the letter 'i'

Answer:
3