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 doughnut held in a persons hand'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a few men walking through a market place'. Find frequency of the letter 'f'

Output: 1


Input: Consider Input: Sentence: 'two street signs over a high way'. Find frequency of the letter 'i'


Output: 2