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

Ex Input:
Sentence: 'slices of orange are arranged on a plate'. Find frequency of the letter 's'

Ex Output:
2


Ex Input:
Sentence: 'a man walking a large elephant down a dirt road'. Find frequency of the letter 'g'

Ex Output:
2


Ex Input:
Sentence: 'a bunch of cars and motorcycles parked on the side of the road'. Find frequency of the letter 'y'

Ex Output:

1