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

Ex Input:
Sentence: 'a family sitting at a table in a restaurant looking at their phones'. Find frequency of the letter 't'

Ex Output:
8


Ex Input:
Sentence: 'a bunch of green bananas is hanging on a tree'. Find frequency of the letter 'n'

Ex Output:
7


Ex Input:
Sentence: 'a man at the beach pulling a surf board out'. Find frequency of the letter 'n'

Ex Output:

2