instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a herd of giraffes in tall african grass'. Find frequency of the letter 'a'
answer:
6


question:
Sentence: 'a large cooked pizza on a dining table'. Find frequency of the letter 'n'
answer:
3


question:
Sentence: 'the train is going down the railroad tracks'. Find frequency of the letter 'g'
answer:

2