#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<int>
#define pb push_back
#define REP(i,n) for(int i = 0; i < n; i++)
#define FOR(i,a,b) for(int i = a; i < b; i++)
int n;
vi a;
ll ans = 0;
bool paired(int ind){
if(ind >= 2*n-1 or ind < 0) return 0;
return (a[ind]+a[ind+1] == 0 and a[ind] < a[ind+1]);
}
int last[200005];
bool exis[200005];
ll count_swaps(vector<int> s) {
n = s.size()/2;
a = s;
REP(i,2*n){
if(exis[n-a[i]]){
ans += i-last[n-a[i]]-1;
if(a[i] < 0) ans++;
REP(j,2*n+1){
if(last[j] > last[n-a[i]])
last[j]++;
}
exis[n+a[i]] = 0;
exis[n-a[i]] = 0;
}
else{
exis[n+a[i]] = 1;
last[n+a[i]] = i;
}
// cout << i << " " << ans << endl;
}
return ans;
}
