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

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 stop sign next to houses with christmas lights'. Find frequency of the letter 's'

Output: 7


Input: Consider Input: Sentence: 'man wearing coat and hat posing for photo in front of wall'. Find frequency of the letter 'o'


Output: 7