#include <bits/stdc++.h>
#include "shoes.h"
using namespace std;
#define FOR(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define sqr(x) ((ll)(x))*(x)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
int N;
stack<int> ofSz[100003];
ll count_swaps(vi S) {
N = sz(S)/2;
for (int i = 2*N-1; i >= 0; i--) ofSz[abs(S[i])].push(i);
ll ans = 0;
vector<pii> pairs;
FOR(i, 1, N+1) {
while (!ofSz[i].empty()) {
int a = ofSz[i].top(); ofSz[i].pop();
pairs.emplace_back(a, ofSz[i].top()); ofSz[i].pop();\
if (S[a] > 0) ans++;
}
}
sort(all(pairs));
set<int> moved;
for (pii i : pairs) {
ans += i.second - i.first - 1 - distance(moved.begin(), moved.lower_bound(i.second));
moved.insert(i.second);
}
return ans;
}
