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

Ex Input:
Sentence: 'a piece of bread stuffed with meat and vegetables'. Find frequency of the letter 's'

Ex Output:
2


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 few guys stand ready to play baseball'. Find frequency of the letter 'o'

Ex Output:

1