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

Input: Consider Input: Sentence: 'a yellow fire hydrant in the forefront of a roadway'. Find frequency of the letter 'r'

Output: 5


Input: Consider Input: Sentence: 'three young people goofing around; one of the guys has a football, the girl has a teddy bear'. Find frequency of the letter 'd'

Output: 3


Input: Consider Input: Sentence: 'a display with giant tooth brushes in a building'. Find frequency of the letter 'p'


Output: 1