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

Input: Consider Input: Sentence: 'a family out snow skiing on a blustery day'. Find frequency of the letter 'i'

Output: 3


Input: Consider Input: Sentence: 'a street at night with trees and streetlights on'. Find frequency of the letter 't'

Output: 9


Input: Consider Input: Sentence: 'a red train traveling down train tracks near a forest'. Find frequency of the letter 'f'


Output: 1