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

Input: Consider Input: Sentence: 'a guy surfs a wave with his surfboard'. Find frequency of the letter 's'

Output: 4


Input: Consider Input: Sentence: 'a photo of a toilet which is not clean'. Find frequency of the letter 'w'

Output: 1


Input: Consider Input: Sentence: 'two black and white clocks a tan building and a white and blue bus'. Find frequency of the letter 'h'


Output: 2