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

Input: Consider Input: Sentence: 'two men sitting quietly on a park bench'. Find frequency of the letter 'a'

Output: 2


Input: Consider Input: Sentence: 'a dog on a couch near many pillows'. Find frequency of the letter 'p'

Output: 1


Input: Consider Input: Sentence: 'a young man is running to hit a tennis ball'. Find frequency of the letter 'i'


Output: 4