instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a small wrinkley dog wearing a bow tie'. Find frequency of the letter 'e'
answer:
3


question:
Sentence: 'old double decker bus parked in a lot'. Find frequency of the letter 't'
answer:
1


question:
Sentence: 'a small boat and a large boat on a river near a city'. Find frequency of the letter 'a'
answer:

10