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

Ex Input:
Sentence: 'a closeup view of a bathroom sink, that is very modern'. Find frequency of the letter 'e'

Ex Output:
4


Ex Input:
Sentence: 'a man holding a brown paper bag kite'. Find frequency of the letter 'b'

Ex Output:
2


Ex Input:
Sentence: 'two partially nude young women are holding sandwiches'. Find frequency of the letter 'w'

Ex Output:

3