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

Input: Consider Input: Sentence: 'a closet with a fan, luggage and various boxes'. Find frequency of the letter 'a'

Output: 6


Input: Consider Input: Sentence: 'a dog has found a rather large stick for playing fetch'. Find frequency of the letter 't'

Output: 3


Input: Consider Input: Sentence: 'two red vintage tour buses parked in a field'. Find frequency of the letter 'n'


Output: 2


