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

Input: Consider Input: Sentence: 'a group of people walking down a rain soaked street with umbrellas'. Find frequency of the letter 'w'

Output: 3


Input: Consider Input: Sentence: 'a gray colored pigeon that is perched on a railing outside of a building, with other buildings in the background'. Find frequency of the letter 'e'

Output: 7


Input: Consider Input: Sentence: 'vegetables line the shelves in a room where they are prepared'. Find frequency of the letter 'e'


Output: 13