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

Input: Consider Input: Sentence: 'people plating cake in an office meeting room'. Find frequency of the letter 'g'

Output: 2

Input: Consider Input: Sentence: 'a group of people having dinner and drinking wine'. Find frequency of the letter 'r'

Output: 3

Input: Consider Input: Sentence: 'a group of people on motor bikes on a road'. Find frequency of the letter 'g'
Output: 1