#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];
vi gg1[200005],gg2[200005];
int seg[400005];
void upd(int ind,int val){
ind += 2*n;
while(ind){
seg[ind] += val;
ind /= 2;
}
}
int quer(int l,int r){
l += 2*n;
r += 2*n+1;
int res = 0;
while(l < r){
if(l%2) res += seg[l++];
if(r%2) res += seg[--r];
l /= 2;
r /= 2;
}
return res;
}
ll count_swaps(vector<int> s) {
n = s.size()/2;
a = s;
REP(i,2*n){
if(a[i] < 0) gg1[-a[i]].pb(i);
else gg2[a[i]].pb(i);
}
int cur = 1;
FOR(i,1,n+1){
REP(j,(int)gg1[i].size()){
a[gg1[i][j]] = -cur;
a[gg2[i][j]] = cur;
cur++;
}
}
REP(i,2*n){
if(exis[n-a[i]]){
ans += i-last[n-a[i]]-1;
if(a[i] < 0) ans++;
ans -= quer(0,last[n-a[i]]);
upd(last[n-a[i]],1);
upd(i,-1);
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;
}
