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

Input: Consider Input: Sentence: 'a picture of a machine built next to a street'. Find frequency of the letter 'x'

Output: 1


Input: Consider Input: Sentence: 'a parking meter painted green with a sign that describes it as not a parking meter'. Find frequency of the letter 's'

Output: 4


Input: Consider Input: Sentence: 'a young boy holding a baseball bat while standing on a baseball field'. Find frequency of the letter 'a'


Output: 9