instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a double decker bus with a lot of people on board'. Find frequency of the letter 'l'
answer:
3


question:
Sentence: 'a small boat travels on the water next to the shore'. Find frequency of the letter 'a'
answer:
5


question:
Sentence: 'a street with cars on it is shown'. Find frequency of the letter 'w'
answer:

2