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 plane with stairs next to it sitting in a large lot'. Find frequency of the letter 'i'

Answer: 6


Question: Sentence: 'a group of tennis players on a tennis court'. Find frequency of the letter 'o'

Answer: 4


Question: Sentence: 'a young person prepares to swing at a pitch on a grassy playing field'. Find frequency of the letter 's'

Answer:
5