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 person riding a surfboard in the middle of a wave'. Find frequency of the letter 'o'

Answer: 3

Question: Sentence: 'a woman standing in front of a bathroom sink in front of a mirror'. Find frequency of the letter 'o'

Answer: 8

Question: Sentence: 'woman seated on a park bench, reading and listening to music player'. Find frequency of the letter 'r'

Answer:
3