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

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 man is water skiing on a river'. Find frequency of the letter 'r'

Output: 3


Input: Consider Input: Sentence: 'three men on motorcycles sit in front of a western style building'. Find frequency of the letter 'o'


Output: 5