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

Input: Consider Input: Sentence: 'a ready to eat pizza on a rack'. Find frequency of the letter 'r'

Output: 2


Input: Consider Input: Sentence: 'wooden and black bench on the side of the road'. Find frequency of the letter 'a'

Output: 3


Input: Consider Input: Sentence: 'a black cat laying in a sink on top of clothing'. Find frequency of the letter 'n'


Output: 5