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

Input: Consider Input: Sentence: 'a large cooked pizza on a dining table'. Find frequency of the letter 'n'

Output: 3

Input: Consider Input: Sentence: 'a woman walking with a child that is in a wheelchair'. Find frequency of the letter 'k'

Output: 1

Input: Consider Input: Sentence: 'i'm sorry i have no idea what this is'. Find frequency of the letter 'h'
Output: 3