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

Ex Input:
Sentence: 'two zebra stand near the wooden posts on a building'. Find frequency of the letter 't'

Ex Output:
4


Ex Input:
Sentence: 'a person holding a wine glass in one hand and bread sticks in the other'. Find frequency of the letter 'd'

Ex Output:
4


Ex Input:
Sentence: 'a gourmet looking hamburger with fries on a dining table with some wine'. Find frequency of the letter 't'

Ex Output:

4