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

Input: Consider Input: Sentence: 'small black bird with red on its head standing on a tree branch'. Find frequency of the letter 'b'

Output: 3


Input: Consider Input: Sentence: 'a bird outside standing on a table looking up'. Find frequency of the letter 'b'

Output: 2


Input: Consider Input: Sentence: 'a traffic signal with a orange bicycle emblem on at the top'. Find frequency of the letter 'f'


Output: 2