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

Ex Input:
Sentence: 'a bedroom with a neatly made bed and a laptop'. Find frequency of the letter 'l'

Ex Output:
2


Ex Input:
Sentence: 'food sitting in bowls on table with checked tablecloth'. Find frequency of the letter 't'

Ex Output:
6


Ex Input:
Sentence: 'the dark bedroom has two dressers and a chair in the corner'. Find frequency of the letter 's'

Ex Output:

4