instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'several zebras  and a giraffe in an enclosure'. Find frequency of the letter 's'
answer:
3


question:
Sentence: 'a row of vintage cars in a grassy field'. Find frequency of the letter 'v'
answer:
1


question:
Sentence: 'an elephant standing on top of a grassy field'. Find frequency of the letter 't'
answer:

3