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

Input: Consider Input: Sentence: 'a cat sprawls out and sleeps on its back on a lounge chair with an acorn theme'. Find frequency of the letter 'r'

Output: 3


Input: Consider Input: Sentence: 'a dog is shown sitting on rocks by the beach'. Find frequency of the letter 'a'

Output: 2


Input: Consider Input: Sentence: 'a group of workers washing and cleaning fruits and vegetables'. Find frequency of the letter 'i'


Output: 3