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 couple of men sitting next to each other under an umbrella'. Find frequency of the letter 'n'

Output: 5


Input: Consider Input: Sentence: 'the are looking at a deep dish pizza with a slice removed'. Find frequency of the letter 'e'


Output: 7