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

Input: Consider Input: Sentence: 'two elephants walking on cement next to wall'. Find frequency of the letter 'n'

Output: 5


Input: Consider Input: Sentence: 'a microwave oven with a yellow note on the door'. Find frequency of the letter 'w'

Output: 3


Input: Consider Input: Sentence: 'a typical residential bathroom, including sink, toilet, and bathtub'. Find frequency of the letter 'e'


Output: 3