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

Ex Input:
Sentence: 'a young girl is brushing her teeth in this dated photo'. Find frequency of the letter 't'

Ex Output:
5


Ex Input:
Sentence: 'a tall building with antenna stands before a jet flying in the background'. Find frequency of the letter 't'

Ex Output:
6


Ex Input:
Sentence: 'a full plate of food that includes rice and broccoli and carrots'. Find frequency of the letter 's'

Ex Output:

2