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

Ex Input:
Sentence: 'a woman sitting in front of a giant slice of cheese pizza'. Find frequency of the letter 'e'

Ex Output:
4


Ex Input:
Sentence: 'the miniature, elaborate exhibit depicts an ancient boating scene'. Find frequency of the letter 'n'

Ex Output:
6


Ex Input:
Sentence: 'a female tennis player hitting a ball with a racket'. Find frequency of the letter 'c'

Ex Output:

1