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

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 cat that is standing next to an open suitcase'. Find frequency of the letter 'e'

Output: 3


Input: Consider Input: Sentence: 'an open cell phone in a man's hand'. Find frequency of the letter 'h'


Output: 2