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

Input: Consider Input: Sentence: 'a bunch of broken down trains sit in a yard'. Find frequency of the letter 'n'

Output: 5


Input: Consider Input: Sentence: 'a traffic signal by a wire filled with some birds'. Find frequency of the letter 'e'

Output: 3


Input: Consider Input: Sentence: 'dog and bird loose on a floor, with a cat behind a glass door, glowering at the bird'. Find frequency of the letter 'w'


Output: 2