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

Input: Consider Input: Sentence: 'a stop sign next to houses with christmas lights'. Find frequency of the letter 's'

Output: 7


Input: Consider Input: Sentence: 'a small boat and a large boat on a river near a city'. Find frequency of the letter 'a'

Output: 10


Input: Consider Input: Sentence: 'vegetable and rice dinner dish served in white dish'. Find frequency of the letter 's'


Output: 3