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

Input: Consider Input: Sentence: 'a person on a sidewalk jumping with an umbrella'. Find frequency of the letter 'a'

Output: 5


Input: Consider Input: Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'

Output: 5


Input: Consider Input: Sentence: 'sandwich and soup on plates sitting on table'. Find frequency of the letter 'l'


Output: 2