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

Input: Consider Input: Sentence: 'a man in a black shirt prepares to catch a frisbee'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'some giraffes moving across a big grass field'. Find frequency of the letter 'e'

Output: 3


Input: Consider Input: Sentence: 'a baby sits in a high chair and smiles'. Find frequency of the letter 'a'


Output: 5