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 riding a skate board on a city street'. Find frequency of the letter 'a'

Output: 5


Input: Consider Input: Sentence: 'a glass vase sits between two statues'. Find frequency of the letter 'o'

Output: 1


Input: Consider Input: Sentence: 'a plate topped with meat, broccoli and a suace'. Find frequency of the letter 'a'


Output: 6