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

Input: Consider Input: Sentence: 'a cat that is standing next to an open suitcase'. Find frequency of the letter 'e'

Output: 3

Input: Consider Input: Sentence: 'a man standing in front of a statue near a metal pole'. Find frequency of the letter 'f'

Output: 2

Input: Consider Input: Sentence: 'a picture of a person that is buy some food'. Find frequency of the letter 'a'
Output: 3