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

Input: Consider Input: Sentence: 'a picture of two computers on a table'. Find frequency of the letter 'r'

Output: 2


Input: Consider Input: Sentence: 'a photo of a couple of people at a convention'. Find frequency of the letter 'v'

Output: 1


Input: Consider Input: Sentence: 'a classic motorcycle is parked in a driveway'. Find frequency of the letter 'c'


Output: 4