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 girl sits on a surfboard and smiles'. Find frequency of the letter 'i'

Answer: 3


Question: Sentence: 'a man playing baseball on a television set'. Find frequency of the letter 'l'

Answer: 4


Question: Sentence: 'train blowing smoke as it comes around the bend of the tracks'. Find frequency of the letter 't'

Answer:
5