instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a blue tripocal bird is perched on a wooden fence'. Find frequency of the letter 'd'
answer:
3


question:
Sentence: 'two metal  benches on an empty train platform'. Find frequency of the letter 'n'
answer:
4


question:
Sentence: 'a sailboat is floating near the rocky shore of a beach'. Find frequency of the letter 'o'
answer:

5