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 tennis players on a tennis court'. Find frequency of the letter 'o'

Output: 4


Input: Consider Input: Sentence: 'two people are riding on canoes down a river'. Find frequency of the letter 'e'

Output: 5


Input: Consider Input: Sentence: 'two plates of food next to two laptops'. Find frequency of the letter 'o'


Output: 7