instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a person standing operating a cell phone in a room'. Find frequency of the letter 'n'
answer:
6


question:
Sentence: 'small black bird with red on its head standing on a tree branch'. Find frequency of the letter 'b'
answer:
3


question:
Sentence: 'electric guitar player using a musical keyboard and a laptop'. Find frequency of the letter 'e'
answer:

4