instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a picture of two computers on a table'. Find frequency of the letter 'r'
answer:
2


question:
Sentence: 'a gray elephant is in a grassy field'. Find frequency of the letter 'e'
answer:
3


question:
Sentence: 'a boy and a girl pointing to a roll on a plate'. Find frequency of the letter 'd'
answer:

1


