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

Ex Input:
Sentence: 'a young elephant is touching a bigger elephant with its trunk'. Find frequency of the letter 'i'

Ex Output:
5


Ex Input:
Sentence: 'a little boy standing near a couch and a table'. Find frequency of the letter 'i'

Ex Output:
2


Ex Input:
Sentence: 'two garbage collectors standing behind a garbage truck gathering up bags'. Find frequency of the letter 'h'

Ex Output:

2