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

Input: Consider Input: Sentence: 'the street sign is next to a curved road'. Find frequency of the letter 's'

Output: 3


Input: Consider Input: Sentence: 'two computers and a laptop set up on a desk'. Find frequency of the letter 'r'

Output: 1


Input: Consider Input: Sentence: 'a person jumping up into the air on a skateboard'. Find frequency of the letter 'i'


Output: 3