instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a blue train on a track next to another track'. Find frequency of the letter 'c'
answer:
2


question:
Sentence: 'a young man riding a skateboard near a forest'. Find frequency of the letter 'd'
answer:
2


question:
Sentence: 'a mix of zebra and possibly horse stands in the grass'. Find frequency of the letter 'a'
answer:

5