In this task, you need to count the number of times the given letter appears in the given sentence.
--------
Question: Sentence: 'a man paddle boarding by a boat dock in a city'. Find frequency of the letter 'o'

Answer: 3


Question: Sentence: 'there is a sandwich with a lot of meat cut in half'. Find frequency of the letter 'a'

Answer: 5


Question: Sentence: 'a man sits on a pile of logs beside his horse'. Find frequency of the letter 'b'

Answer:
1