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

Input: Consider Input: Sentence: 'a man serving himself pizza in a wooden booth'. Find frequency of the letter 'n'

Output: 4


Input: Consider Input: Sentence: 'a group of people walking down a rain soaked street with umbrellas'. Find frequency of the letter 'w'

Output: 3


Input: Consider Input: Sentence: 'a group of men standing and sitting with sitting men holding up a cake'. Find frequency of the letter 's'


Output: 3