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

Ex Input:
Sentence: 'a child sitting a table with a pizza in front of him'. Find frequency of the letter 'h'

Ex Output:
3


Ex Input:
Sentence: 'a man holding a frisbee high into the air'. Find frequency of the letter 'a'

Ex Output:
4


Ex Input:
Sentence: 'zebra eating hay in a zoo like environment'. Find frequency of the letter 'g'

Ex Output:

1