instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a green bus driving in a street filled with heavy traffic'. Find frequency of the letter 'v'
answer:
2

question:
Sentence: 'a laptop computer with pictures of giraffes on the homescreen'. Find frequency of the letter 'o'
answer:
5

question:
Sentence: 'underside of a passenger jet flying low to the ground at night'. Find frequency of the letter 'n'
answer:
5