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 little boy that has a toothbrush in his mouth'. Find frequency of the letter 'r'

Answer: 1


Question: Sentence: 'a person standing operating a cell phone in a room'. Find frequency of the letter 'n'

Answer: 6


Question: Sentence: 'a room that has a very low ceiling'. Find frequency of the letter 'l'

Answer:
2