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

Input: Consider Input: Sentence: 'a picture of two men on a motorcycle in front of a railroad track'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'the man is holding a plastic sled with snow in it next to a child'. Find frequency of the letter 'g'

Output: 1


Input: Consider Input: Sentence: 'a calf walking into a stall looking at another calf that is bleeding'. Find frequency of the letter 's'


Output: 2