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

Ex Input:
Sentence: 'a bird in a tree looking up at branches'. Find frequency of the letter 'e'

Ex Output:
3


Ex Input:
Sentence: 'a man is taking a picture of a man and woman'. Find frequency of the letter 'a'

Ex Output:
8


Ex Input:
Sentence: 'native man standing with goat in fenced outdoor area'. Find frequency of the letter 'g'

Ex Output:

2