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

Input: Consider Input: Sentence: 'a group of three dogs laying on a kitchen floor'. Find frequency of the letter 'r'

Output: 3


Input: Consider Input: Sentence: 'a couple of buses parked on the side of the street'. Find frequency of the letter 'b'

Output: 1


Input: Consider Input: Sentence: 'mans bathroom with two visible fixtures, trash basket and plunger in sight'. Find frequency of the letter 'a'


Output: 5