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

Input: Consider Input: Sentence: 'three birds are sitting on a tree in a forest'. Find frequency of the letter 'h'

Output: 1


Input: Consider Input: Sentence: 'a truck with a camper sits parked in some vegetation'. Find frequency of the letter 's'

Output: 3


Input: Consider Input: Sentence: 'the train passes by a bridge over a lake'. Find frequency of the letter 'v'


Output: 1