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

Input: Consider Input: Sentence: 'a white toilet sitting next to a toilet paper roller'. Find frequency of the letter 'o'

Output: 4


Input: Consider Input: Sentence: 'large grassy pasture filled with trees and a single horse'. Find frequency of the letter 'l'

Output: 4


Input: Consider Input: Sentence: 'a young girl kneeling in front of a refrigerator freezer'. Find frequency of the letter 'r'


Output: 8