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

Input: Consider Input: Sentence: 'a doorway looking into a small bathroom with white toilet'. Find frequency of the letter 'r'

Output: 2


Input: Consider Input: Sentence: 'the meal is served and ready to be eaten'. Find frequency of the letter 'e'

Output: 8


Input: Consider Input: Sentence: 'a couple of cows standing around behind a fenced in area'. Find frequency of the letter 'a'


Output: 6