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

Input: Consider Input: Sentence: 'a tower with some bright lights and clocks on it'. Find frequency of the letter 'h'

Output: 3

Input: Consider Input: Sentence: 'person wearing all white leaned up against a wall with a yellow sign'. Find frequency of the letter 'a'

Output: 8

Input: Consider Input: Sentence: 'a couple of items that are on the wall'. Find frequency of the letter 'm'
Output: 1