Problem Statement
Snuke received ~N~ intervals as a birthday present. The ~i~ -th interval was ~[-L_i, R_i]~ . It is guaranteed that both ~L_i~ and ~R_i~ are positive. In other words, the origin is strictly inside each interval.
Snuke doesn't like overlapping intervals, so he decided to move some intervals. For any positive integer ~d~ , if he pays ~d~ dollars, he can choose one of the intervals and move it by the distance of ~d~ . That is, if the chosen segment is ~[a, b]~ , he can change it to either ~[a+d, b+d]~ or ~[a-d, b-d]~ .
He can repeat this type of operation arbitrary number of times. After the operations, the intervals must be pairwise disjoint (however, they may touch at a point). Formally, for any two intervals, the length of the intersection must be zero.
Compute the minimum cost required to achieve his goal.
Constraints
- ~1 ≤ N ≤ 5000~
- ~1 ≤ L_i, R_i ≤ 10^9~
- All values in the input are integers.
Input
The input is given from Standard Input in the following format:
~N~
~L_1~ ~R_1~
~L_N~ ~R_N~
Output
Print the minimum cost required to achieve his goal.
Sample Input 1
4
2 7
2 5
4 1
7 5
Sample Output 1
22
One optimal solution is as follows:
- Move the interval ~[-2, 7]~ to ~[6, 15]~ with ~8~ dollars
- Move the interval ~[-2, 5]~ to ~[-1, 6]~ with ~1~ dollars
- Move the interval ~[-4, 1]~ to ~[-6, -1]~ with ~2~ dollars
- Move the interval ~[-7, 5]~ to ~[-18, -6]~ with ~11~ dollars
The total cost is ~8 + 1 + 2 + 11 = 22~ dollars.
Sample Input 2
20
97 2
75 25
82 84
17 56
32 2
28 37
57 39
18 11
79 6
40 68
68 16
40 63
93 49
91 10
55 68
31 80
57 18
34 28
76 55
21 80
Sample Output 2
7337
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