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

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 girl playing with a frisbee while people watch'. Find frequency of the letter 'e'

Ex Output:
5


Ex Input:
Sentence: 'a bowl of fruit is on the floor in front of some feet'. Find frequency of the letter 't'

Ex Output:

4