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

Input: Consider Input: Sentence: 'group of snowboarders on a snowy trail overlooking a mountain'. Find frequency of the letter 'r'

Output: 5


Input: Consider Input: Sentence: 'man sitting on the side of a van playing the guitar'. Find frequency of the letter 'm'

Output: 1


Input: Consider Input: Sentence: 'a dining table and some chairs in a kitchen'. Find frequency of the letter 'a'


Output: 5