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

Input: Consider Input: Sentence: 'a notebook and pen are left on a park bench'. Find frequency of the letter 'e'

Output: 5


Input: Consider Input: Sentence: 'a person riding a surfboard in the middle of a wave'. Find frequency of the letter 'o'

Output: 3


Input: Consider Input: Sentence: 'a mostly white kitchen has dishes in the sink'. Find frequency of the letter 'e'


Output: 4