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: 'guy leans on truck's hood while taking pics next to parked motorcycles'. Find frequency of the letter 's'

Ex Output:
4


Ex Input:
Sentence: 'a person sitting outdoors with a frisbee in front of their face'. Find frequency of the letter 'e'

Ex Output:

5