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

Ex Input:
Sentence: 'two people in a snowy place near a wooden fence'. Find frequency of the letter 'n'

Ex Output:
5


Ex Input:
Sentence: 'a couple of people are sitting at a table'. Find frequency of the letter 'e'

Ex Output:
5


Ex Input:
Sentence: 'a woman is walking next to her bike and holding the leash of a dog'. Find frequency of the letter 'k'

Ex Output:

2