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 couple of men sitting next to each other under an umbrella'. Find frequency of the letter 'n'

Answer: 5


Question: Sentence: 'a half eaten doughnut in a persons hand'. Find frequency of the letter 'h'

Answer: 3


Question: Sentence: 'a train on a train track near hills'. Find frequency of the letter 'l'

Answer:
2