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

Input: Consider Input: Sentence: 'a commuter bus in england by a clock tower building'. Find frequency of the letter 'w'

Output: 1


Input: Consider Input: Sentence: 'a man is taking a picture of a man and woman'. Find frequency of the letter 'a'

Output: 8


Input: Consider Input: Sentence: 'a couple of elephants standing next to each other'. Find frequency of the letter 'a'


Output: 4