#include <bits/stdc++.h>
using namespace std;
#define ll long long
ll sub2(vector <int> S) {
int n = S.size() / 2;
vector <int> pre(n + 1, -1);
vector <pair <int, int>> shoes;
for (int i = 0; i < S.size(); i++) {
int p = pre[abs(S[i])];
if (p != -1) {
shoes.emplace_back(p, i), pre[abs(S[i])] = -1;
if (S[p] > 0) swap(shoes.back().first, shoes.back().second);
}
else pre[abs(S[i])] = i;
}
vector <int> permu(n); iota(permu.begin(), permu.end(), 0);
ll res = 1e18;
do {
ll cost = 0; vector <bool> mark(S.size());
for (int pos = 0; pos < S.size(); pos++) {
int sh = (pos & 1) ? shoes[permu[pos >> 1]].second : shoes[permu[pos >> 1]].first;
int real_sh = sh; mark[sh] = true;
for (int i = sh + 1; i < S.size(); i++) real_sh += mark[i];
cost += abs(real_sh - pos);
}
res = min(res, cost);
} while (next_permutation(permu.begin(), permu.end()));
return res;
}
ll sub3(vector <int> S) {
vector <int> L;
for (int i = 0; i < S.size(); i++)
if (S[i] < 0) L.emplace_back(i);
ll ans = 0;
for (int i = 0; i < L.size(); i++)
ans += abs(L[i] - i * 2);
return ans;
}
ll sub4(vector <int> S) {
int n = S.size() / 2; // 1 + ... + n - 1
return 1ll * n * (n - 1) / 2;
}
ll count_swaps(vector <int> S) {
if (S.size() == 2) return (S[0] > 0); // sub1
if (S.size() <= 16) return sub2(S);
bool s3 = true;
for (int i = 1; i < S.size(); i++)
if (abs(S[i - 1]) != abs(S[i])) s3 = false;
if (s3) return sub3(S);
return sub4(S);
}
#ifdef cute
int main() {
cout << count_swaps({2, 1, -1, -2});
}
#endif
