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

Ex Input:
Sentence: 'a few giraffes standing in a field looking around'. Find frequency of the letter 'e'

Ex Output:
3


Ex Input:
Sentence: 'a cat that is standing next to an open suitcase'. Find frequency of the letter 'e'

Ex Output:
3


Ex Input:
Sentence: 'i hope that is face paint on her face and not tattoos'. Find frequency of the letter 'e'

Ex Output:

4