/** gnu specific **/
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/** contains everything I need in std **/
#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(S) ((int)S.size())
#define FOR(i, st_, n) for(int i = st_; i < n; ++i)
#define RFOR(i, n, end_) for(int i = (n)-1; i >= end_; --i)
#define x first
#define y second
#define pb push_back
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef unsigned long long ull;
typedef long double LD;
typedef pair<ull, ull> pull;
using namespace __gnu_pbds;
typedef tree<ll, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
using namespace std;
#ifdef ONPC
mt19937 rnd(228);
#else
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif

struct Req
{
	int l, r;
};



ll compute_answ(int l, int r, vector<int>& a)
{
	set<int> was;
	int res=0;
	for(int i=l;i<=r;++i)
	{
		if(was.find(a[i])==was.end())
		{
			was.insert(a[i]);
		}
		else
		{
			++res;
		}
	}
	return res;
}

int solve()
{
	int n;
	if(!(cin>>n))
		return 1;
	vector<int> a(2*n);
	vector<int> LL(n,-1), RR(n,-1);
	FOR(i,0,2*n)
	{
		int cust,loc;
		cin>>cust>>loc;
		--loc, --cust;
		a[i]=loc;
		if(LL[cust]==-1)LL[cust]=i;
		else RR[cust]=i;
	}
	vector<Req> req(n);
	FOR(i,0,n)req[i]={LL[i],RR[i]};
	ll res=0;

	for(auto [l, r]: req)
		res += compute_answ(l,r,a);
	cout<<res<<'\n';
    return 0;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int TET = 1e9;
    //cin >> TET;
    for (int i = 1; i <= TET; i++)
    {
        if (solve())
        {
            break;
        }
#ifdef ONPC
        cout << "__________________________" << endl;
#endif
    }
#ifdef ONPC
    cerr << endl << "finished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec" << endl;
#endif
}