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 girl playing with a frisbee while people watch'. Find frequency of the letter 'e'

Answer: 5


Question: Sentence: 'a black bear sitting in the grass taking a rest'. Find frequency of the letter 'a'

Answer: 6


Question: Sentence: 'two people and two children walking in a building'. Find frequency of the letter 'd'

Answer:
3