Given $n$ cows, each cow $i$ has an IQ of $a_i$ and an EQ of $b_i$. You want to select some cows (you may select none) such that the sum of their total IQ and EQ is maximized, while the individual sums of IQ and EQ are both non-negative.
### Input
- The first line contains an integer $n$.
- The next $n$ lines each contain two integers $a_i$ and $b_i$.
### Output
- Print a single integer which is the maximum possible sum of the total IQ and EQ of the selected cows.
### Constraints
- $1 \le n \le 500$.
- $|a_i|, |b_i| \le 1000$.
### Example
Input:
```
5
-5 7
8 -6
6 -3
2 1
-8 -5
```
Output:
```
8
```
Explanation:
- Select cows $1$, $3$, and $4$.
- Including cow $2$ would result in a total of $10$, but the total EQ would be negative.
