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

Ex Input:
Sentence: 'supplies and tools are arranged on the floor with a hard hat and bag'. Find frequency of the letter 'n'

Ex Output:
4


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

Ex Output:
2


Ex Input:
Sentence: 'a woman holding a baseball bat in a baseball helmet'. Find frequency of the letter 's'

Ex Output:

2