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

Input: Consider Input: Sentence: 'a desk covered in notepads, a laptop and other devices'. Find frequency of the letter 'c'

Output: 2


Input: Consider Input: Sentence: 'a man opening up a package sitting on a couch'. Find frequency of the letter 'n'

Output: 5


Input: Consider Input: Sentence: 'a red and yellow bus on a city street'. Find frequency of the letter 't'


Output: 3