In this task, you need to count the number of times the given letter appears in the given sentence.

Input: Consider Input: Sentence: 'a group of giraffes walk together by a hill'. Find frequency of the letter 'b'

Output: 1


Input: Consider Input: Sentence: 'a burning wood stove has a tea pot sitting on top of it and is full of wood'. Find frequency of the letter 'a'

Output: 5


Input: Consider Input: Sentence: 'a group of people walking down a street next to buildings'. Find frequency of the letter 'o'

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Output: 5


