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 doorway looking into a small bathroom with white toilet'. Find frequency of the letter 'r'

Answer: 2


Question: Sentence: 'a bed with a mattress that has nothing on it'. Find frequency of the letter 'a'

Answer: 5


Question: Sentence: 'a girl skis first in a line of skiers'. Find frequency of the letter 'r'

Answer:
3