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

Input: Consider Input: Sentence: 'a person standing operating a cell phone in a room'. Find frequency of the letter 'n'

Output: 6

Input: Consider Input: Sentence: 'a woman holds the reins of a saddled horse'. Find frequency of the letter 'm'

Output: 1

Input: Consider Input: Sentence: 'a cat is laying in a bowl with a receipt'. Find frequency of the letter 'o'
Output: 1