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5934: Jeff and Permutation

内存限制：256 MB 时间限制：2 S
题面：传统 评测方式：文本比较 上传者：
提交：2 通过：2
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题目描述

E. Jeff and Permutation
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
Jeff's friends know full well that the boy likes to get sequences and arrays for his birthday. Thus, Jeff got sequence p1,p2,...,pn for his birthday.
Jeff hates inversions in sequences. An inversion in sequence a1,a2,...,an is a pair of indexes i,j (1≤i<j≤n), such that an inequality ai>aj 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.
Input
The first line contains integer n (1≤n≤2000). The next line contains n integers − sequence p1, p2, ..., pn (|pi|≤105). The numbers are separated by spaces.
Output
In a single line print the answer to the problem − the minimum number of inversions Jeff can get.
Examples
Input 
2
2 1
Output 
0
Input 
9
-2 0 -1 0 -1 2 1 0 -1
Output 
6

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