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

Input: Consider Input: Sentence: 'a man in a black shirt prepares to catch a frisbee'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'a couple of items that are on the wall'. Find frequency of the letter 'm'

Output: 1


Input: Consider Input: Sentence: 'a large brown bear standing next to another bear'. Find frequency of the letter 'b'


Output: 3