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

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


Ex Input:
Sentence: 'a baby elephant walks beside an adult elephant along a post and cable'. Find frequency of the letter 'l'

Ex Output:
6


Ex Input:
Sentence: 'a man holding a cigarette standing in a field'. Find frequency of the letter 'l'

Ex Output:

2