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

Input: Consider Input: Sentence: 'a closet with a fan, luggage and various boxes'. Find frequency of the letter 'a'

Output: 6

Input: Consider Input: Sentence: 'a woman with short, brown hair is looking into a circular mirror and holding a camera up to her cheek'. Find frequency of the letter 'e'

Output: 4

Input: Consider Input: Sentence: 'two people sitting down holding cellphones in their hands'. Find frequency of the letter 'p'
Output: 3