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

Ex Input:
Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'

Ex Output:
5


Ex Input:
Sentence: 'a large formal living room with yellow couches and table'. Find frequency of the letter 'v'

Ex Output:
1


Ex Input:
Sentence: 'a beautiful woman laying on top of a bed in lingerie'. Find frequency of the letter 'e'

Ex Output:

4