instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a young elephant is touching a bigger elephant with its trunk'. Find frequency of the letter 'i'
answer:
5


question:
Sentence: 'a couple of buses parked on the side of the street'. Find frequency of the letter 'b'
answer:
1


question:
Sentence: 'a black and white picture of a train'. Find frequency of the letter 't'
answer:

3