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 small white dog looking out a car window'. Find frequency of the letter 'l'

Answer: 3


Question: Sentence: 'a tennis player after hitting a shot back to the other side of the court'. Find frequency of the letter 'n'

Answer: 3


Question: Sentence: 'an elephant with a decorative head band walks behind another elephant in a city'. Find frequency of the letter 'a'

Answer:
10