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

Input: Consider Input: Sentence: 'a row of vintage cars in a grassy field'. Find frequency of the letter 'v'

Output: 1


Input: Consider Input: Sentence: 'a bird is standing on the ledge of the building'. Find frequency of the letter 't'

Output: 3


Input: Consider Input: Sentence: 'a cat is playing with a glass under a table'. Find frequency of the letter 's'


Output: 3