Description

Xiao Ben’s final exams have ended.

His grades will be released soon.

You are given an exam score table, for example:

Of course, the teachers at school think that entering so many grades makes it hard to calculate, so they want you to compute a comprehensive grade evaluation.

The comprehensive grade evaluation is defined as: $(\text{sum of full scores} \times 3 - \text{sum of actual scores} \times 2) \div \text{sum of points deducted for each subject}$.

Xiao Ben wants you to output his comprehensive grade. Can you do it?

Input Format

The first line contains an integer $n$, the total number of subjects.
The second line contains $n$ integers $a_i$, where $a_i$ is the full score of the $i$-th subject.
The third line contains $n$ integers $b_i$, where $b_i$ is Xiao Ben’s actual score in the $i$-th subject.

Output Format

Output one number in a single line, representing his comprehensive grade. Keep $6$ digits after the decimal point.

3
10 10 10
5 5 5

4.000000

Hint

For $20$% of the testdata, the data is the sample.

For $100$% of the testdata, $n \le 1e7$.

Translated by ChatGPT 5