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

Input: Consider Input: Sentence: 'a woman walking with a child that is in a wheelchair'. Find frequency of the letter 'k'

Output: 1


Input: Consider Input: Sentence: 'a photo of a couple of people at a convention'. Find frequency of the letter 'v'

Output: 1


Input: Consider Input: Sentence: 'two children work at a desk on laptop computers'. Find frequency of the letter 'k'


Output: 2