instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a girl playing with a frisbee while people watch'. Find frequency of the letter 'e'
answer:
5


question:
Sentence: 'many different species of sheep in display at a museum'. Find frequency of the letter 'h'
answer:
1


question:
Sentence: 'a group of cats sitting on the ground and on a shelf  in a cage'. Find frequency of the letter 'n'
answer:

6