#include <bits/stdc++.h>
using namespace std;

void just_do_it();

int main() {
	#ifdef KAMIRULEZ
		freopen("kamirulez.inp", "r", stdin);
		freopen("kamirulez.out", "w", stdout);
	#endif
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	just_do_it();
	return 0;
}

const long long inf = 1e18L + 20;
const int maxn = 5e5 + 20;
int a[maxn];
vector<int> groups[maxn];
pair<int, int> vals[maxn];
long long dp[maxn][2];
int bit1[maxn];
int bit2[maxn];
int zero;

void update(int bit[], int pos, int add) {
	for (int i = pos; i < maxn; i += i & (-i)) {
		bit[i] += add;
	}
}

int get(int bit[], int pos) {
	int res = 0;
	for (int i = pos; i > 0; i -= i & (-i)) {
		res += bit[i];
	}
	return res;
}

void calc(vector<int> &group, long long prv_dp[], long long cur_dp[]) {
	if (a[group[0]] == 0) {
		cur_dp[0] = 0;
		cur_dp[1] = 0;
		zero += group.size();
		for (auto pos: group) {
			update(bit1, pos, 1);
		}
		return;
	}
	int n = group.size();
	sort(group.begin(), group.end());
	cur_dp[0] = inf;
	cur_dp[1] = inf;
	vector<int> pos, neg;
	for (int i = 0; i < n; i++){
		if ((a[group[i]] > 0) ^ (group[i] & 1) ^ 1) {
			pos.push_back(group[i]);
		}
		else {
			neg.push_back(group[i]);
		}
	}
	for (int iter = 0; iter < 2; iter++) {
		int sz_pos0 = (int)pos.size();
		int sz_neg0 = (int)neg.size();
		int sz_pos1 = (n - 1) >> 1;
		int sz_neg1 = n - 1 - sz_pos1;
		int sz_pos2 = n >> 1;
		int sz_neg2 = n - sz_pos2;
		if (sz_pos0 < sz_pos1 || sz_neg0 < sz_neg1) {
			pos.swap(neg);
			continue;
		}
		if ((zero & 1) && (sz_pos0 < sz_pos2 || sz_neg0 < sz_neg2)) {
			pos.swap(neg);
			continue;
		}
		vector<int> order;
		for (int i = 0; i < n - 1; i++) {
			if (i & 1) {
				order.push_back(pos[i >> 1]);
			}
			else {
				order.push_back(neg[i >> 1]);
			}
		}
		int cut = -1;
		if (sz_pos0 > sz_pos1) {
			order.push_back(pos.back());
			cut = n - (n & 1);
		}
		else {
			order.push_back(neg.back());
			cut = n - ((n & 1) ^ 1);
		}
		long long cost = 0;
		for (int i = 0; i < n; i++) {
			if (i < cut) {
				cost += get(bit1, order[i]);
			}
			else {
				cost += zero - get(bit1, order[i]);
			}
		}
		for (int i = n - 1; i >= 0; i--) {
			cost += get(bit2, order[i]);
			update(bit2, order[i], 1);
		}
		for (int i = 0; i < n; i++) {
			update(bit2, order[i], -1);
		}
		int step = 2 - (zero & 1);
		while (true) {
			cur_dp[iter] = min(cur_dp[iter], cost + prv_dp[iter ^ (cut & 1)]);
			if (cut < step) {
				break;
			}
			for (int i = 1; i <= step; i++) {
				cost += zero - get(bit1, order[cut - i]) * 2;
			}
			if (step == 2) {
				cost += (order[cut - 2] < order[cut - 1]) ? 1 : -1;
			}
			cut -= step;
		}
		pos.swap(neg);
	}
	zero += n;
	for (auto pos: group) {
		update(bit1, pos, 1);
	}
}

void just_do_it() {
	int n;
	cin >> n;
	vals[0] = {-1, -1};
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
		vals[i] = {abs(a[i]), i};
	}
	sort(vals + 1, vals + n + 1);
	int m = 0;
	for (int i = 1; i <= n; i++) {
		if (vals[i].first != vals[i - 1].first) {
			m++;
		}
		groups[m].push_back(vals[i].second);
	}
	for (int i = 1; i <= m; i++) {
		calc(groups[i], dp[i - 1], dp[i]);
	}
	if (dp[m][0] == inf) {
		cout << -1;
	}
	else {
		cout << dp[m][0];
	}
}