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

Ex Input:
Sentence: 'a woman fully dressed as a geisha'. Find frequency of the letter 'm'

Ex Output:
1


Ex Input:
Sentence: 'a girl playing with a frisbee while people watch'. Find frequency of the letter 'e'

Ex Output:
5


Ex Input:
Sentence: 'a large crowd of people are on the ski mountain'. Find frequency of the letter 'i'

Ex Output:

2