//#define local
#ifndef local
#include "shoes.h"
#endif
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define ll long long
#define fi first
#define se second
#define pb push_back
#define mp make_pair

typedef pair<ll, ll> ii;
typedef pair<ii, ll> iii;
typedef pair<ii, ii> iiii;

const ll N = 3e5 + 5;

const ll oo = 1e18 + 7, mod = 1e9 + 7;

mt19937 rng(1);

ll rnd(ll l, ll r){
	ll temp = rng() % (r - l + 1);
	return abs(temp) + l;
}

ll n;
bool used[N];

ll count_swaps(vector<int> a){
	n = a.size();
	ll ans = 0;
	for(ll i = 0; i < n; i++){
		if(used[i]) continue;
		ll pos = -1;
		for(ll j = i + 1; j < n; j++){
			if(used[j]) continue;
			if(a[j] == -a[i]){
				pos = j;
				break;
			}
			ans++;
		}
		assert(pos >= 0);
		if(a[i] > a[pos]) ans++;
		used[i] = used[pos] = 1;
	}
	return ans;
}

#ifdef local
void process(){
	ll n;
	vector<int> v;
	cin >> n;
	for(ll i = 0; i < 2 * n; i++){
		ll x;
		cin >> x;
		v.pb(x);
	}
	cout << count_swaps(v);
}

signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	freopen("kek.inp", "r", stdin);
	freopen("kek.out", "w", stdout);
	process();
}
#endif