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

Input: Consider Input: Sentence: 'two laptop computers sitting on top of a white table'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'a train sits on a railroad track as a metal awning covers it'. Find frequency of the letter 'l'

Output: 2


Input: Consider Input: Sentence: 'a city street with many different cars driving'. Find frequency of the letter 'a'


Output: 3