instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'some giraffes moving across a big grass field'. Find frequency of the letter 'e'
answer:
3


question:
Sentence: 'a sailboat is floating near the rocky shore of a beach'. Find frequency of the letter 'o'
answer:
5


question:
Sentence: 'there are four small boats on the beach'. Find frequency of the letter 'u'
answer:

1