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 few men walking through a market place'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'a bench sitting near the beach in a grassy area'. Find frequency of the letter 'y'


Output: 1