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

Input: Consider Input: Sentence: 'a chair and umbrella on a sandy beach'. Find frequency of the letter 's'

Output: 1


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: 'five men cut a cake at an event'. Find frequency of the letter 't'


Output: 3