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

Input: Consider Input: Sentence: 'a person trying to flip a skateboard in a garage'. Find frequency of the letter 'a'

Output: 7


Input: Consider Input: Sentence: 'city two way street with cars lined up on both sides'. Find frequency of the letter 'h'

Output: 2


Input: Consider Input: Sentence: 'the group of girls walk down a flight of stairs carrying umbrellas'. Find frequency of the letter 'a'


Output: 5