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

Input: Consider Input: Sentence: 'a piece of bread stuffed with meat and vegetables'. Find frequency of the letter 's'

Output: 2


Input: Consider Input: Sentence: 'some sheep are standing in a grassy field'. Find frequency of the letter 'n'

Output: 3


Input: Consider Input: Sentence: 'there is a red stop sign on the street'. Find frequency of the letter 'a'


Output: 1