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

Input: Consider Input: Sentence: 'a small wrinkley dog wearing a bow tie'. Find frequency of the letter 'e'

Output: 3


Input: Consider Input: Sentence: 'a bird on a tree is flapping its wings'. Find frequency of the letter 'o'

Output: 1


Input: Consider Input: Sentence: 'a large white airplane next to some people'. Find frequency of the letter 'a'


Output: 4