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

Ex Input:
Sentence: 'there is a woman pointing at something with her dog'. Find frequency of the letter 'i'

Ex Output:
5


Ex Input:
Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'

Ex Output:
5


Ex Input:
Sentence: 'a man looks at a huge pile of green bananas'. Find frequency of the letter 'e'

Ex Output:

4