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

Input: Consider Input: Sentence: 'a person standing operating a cell phone in a room'. Find frequency of the letter 'n'

Output: 6


Input: Consider Input: Sentence: 'a person riding a skate board on a city street'. Find frequency of the letter 'a'

Output: 5


Input: Consider Input: Sentence: 'a peacock with its feather out standing next to a stone wall'. Find frequency of the letter 'o'


Output: 4