#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define ss second
#define ff first
using namespace std;
ll df[1234567],ans;
vector<ll> vv[1234567];
struct segtree{
ll n;
vector<ll>d;
segtree(ll n){
d.resize(4*n);
build(1,1,n);
}
void build(ll v, ll l, ll r){
if(l == r){
d[v] = 1;
return;
}
ll m = (l+r)/2;
build(v*2,l,m);
build(v*2+1,m+1,r);
d[v] = d[v*2]+d[v*2+1];
}
void update(ll v,ll l, ll r, ll pos, ll val){
if(pos < l or pos > r)return;
if(l == r){
d[v] = val;
return;
}
ll m = (l+r)/2;
update(v*2,l,m,pos,val);
update(v*2+1,m+1,r,pos,val);
d[v] = d[v*2]+d[v*2+1];
}
ll query(ll v, ll l, ll r, ll L, ll R){
if(R<L||R<l||r<L) return 0ll;
if(L<=l&&r<=R) return d[v];
ll m = (l+r)/2;
return query(v*2,l,m,L,R) + query(v*2+1,m+1,r,L,R);
}
};
int count_swaps(vector<int> a){
int n = a.size() / 2;
vector<ll> s(1, 0);
for(auto x : a) s.pb(x);
map<ll, vector<ll>> w;
for(ll i = 1; i < s.size(); i++){
w[s[i]].pb(i);
}
segtree seg(2 * n);
vector<pair<ll, ll>> v;
ll cnt = 0;
for(ll i = 1; i <= 100000; i++){
if(w.find(i) == w.end() || w.find(-i) == w.end()) continue;
if(w[i].size() != w[-i].size()) return -1;
for(ll j = 0; j < w[i].size(); j++){
ll x = w[-i][j];
ll y = w[i][j];
if(x < y){
v.pb({x + 1, y - 1});
} else {
v.pb({x - 1, y + 1});
cnt++;
}
}
}
sort(v.begin(), v.end());
for(auto [l, r] : v){
cnt += seg.query(1, 1, 2 * n, l, r);
seg.update(1, 1, 2 * n, r + 1, 0);
}
return cnt;
}
