Jeff and Permutation

给出数组a ,你可以改变每个数的正负，求逆序对数最少是多少 翻译贡献者UID：35873

Jeff's friends know full well that the boy likes to get sequences and arrays for his birthday. Thus, Jeff got sequence $ p_{1},p_{2},...,p_{n} $ for his birthday. Jeff hates inversions in sequences. An inversion in sequence $ a_{1},a_{2},...,a_{n} $ is a pair of indexes $ i,j $ $ (1<=i<j<=n) $ , such that an inequality $ a_{i}>a_{j} $ holds. Jeff can multiply some numbers of the sequence $ p $ by -1. At that, he wants the number of inversions in the sequence to be minimum. Help Jeff and find the minimum number of inversions he manages to get.

The first line contains integer $ n $ $ (1<=n<=2000) $ . The next line contains $ n $ integers — sequence $ p_{1} $ , $ p_{2} $ , $ ... $ , $ p_{n} $ $ (|p_{i}|<=10^{5}) $ . The numbers are separated by spaces.

In a single line print the answer to the problem — the minimum number of inversions Jeff can get.

2
2 1

0

9
-2 0 -1 0 -1 2 1 0 -1

6