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

Input: Consider Input: Sentence: 'a room with a big screen television and a couch'. Find frequency of the letter 'h'

Output: 2


Input: Consider Input: Sentence: 'a bed with a mattress that has nothing on it'. Find frequency of the letter 'a'

Output: 5


Input: Consider Input: Sentence: 'single engine plane parked on a beach near an all-terrain vehicle'. Find frequency of the letter 'n'


Output: 8