instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'two bears swim in a blue pool of water'. Find frequency of the letter 'o'
answer:
4


question:
Sentence: 'wooden and black bench on the side of the road'. Find frequency of the letter 'a'
answer:
3


question:
Sentence: 'a black double decker bus with yellow lettering'. Find frequency of the letter 'e'
answer:

6