#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;
const ll Nm = 262144; const ll E = 18;
vector<ll> st(2*Nm,0); //segtree
ll v2(ll x) {
if (x==0) {
return 100;
}
return __builtin_ctz(x);
}
void upd(ll x, ll v) {
ll p = x+Nm;
do {
st[p]+=v;
p=p/2;
} while (p>0);
}
void init(ll N) {
st = vector<ll>(2*Nm,0LL);
for (ll i=0;i<(2*N);i++) {
upd(i,1);
}
}
ll qry(ll a, ll b) {
if (a>b) {
return 0;
}
if (v2(a)<v2(b+1)) {
ll la = v2(a);
return (st[(a>>la)+(1LL<<(E-la))]+qry(a+(1LL<<la),b));
} else {
ll lb = v2(b+1);
return (st[(b>>lb)+(1LL<<(E-lb))]+qry(a,b-(1LL<<lb)));
}
}
ll count_swaps(vector<int> S) {
ll N = S.size()/2;
init(N);
ll ans = 0;
set<pii> sl; //left shoe: {x,#}
set<ll> sr[N+1]; //right shoe: # -> x
for (ll x=0;x<(2*N);x++) {
ll y = S[x];
if (y<0) {
sl.insert({x,-y});
} else {
sr[y].insert(x);
}
}
while (!sl.empty()) {
pii p0 = *sl.begin(); sl.erase(sl.begin());
ans += qry(0,p0.first-1);
upd(p0.first,-1);
ll xf = *sr[p0.second].begin(); sr[p0.second].erase(sr[p0.second].begin());
ans += qry(0,xf-1);
upd(xf,-1);
}
return ans;
}
// int main() {
// ll N; cin >> N;
// vector<int> S0;
// for (ll i=0;i<(2*N);i++) {
// ll t; cin >> t;
// S0.push_back(t);
// }
// cout << count_swaps(S0);
// }
