#include <atcoder/all>
#include <bits/stdc++.h>
using ll = long long;
using ull = unsigned long long;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define REP(i, m, n) for(int i = (int)(m); i < (int)(n); i++)
using namespace std;
using namespace atcoder;
using mint = modint998244353;
const int inf = 1000000007;
const ll longinf = 1ll << 60;

double calculate_score(ll x) {
    return 2000000 - 100000 * log10(abs(x - (ll)5e17) + 1);
}

void output(vector<pair<int, int>> &query) {
    for(auto [l, r] : query) {
        cout << l + 1 << " " << r + 1 << endl;
    }
}

void do_query(vector<ll> &a, vector<ll> &b, int i, int j) {
    ll x = (a[i] + a[j]) / 2;
    ll y = (b[i] + b[j]) / 2;
    a[i] = a[j] = x;
    b[i] = b[j] = y;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    vector<ll> a(n), b(n);
    rep(i, n) cin >> a[i] >> b[i];
    vector<pair<int, int>> query;
    rep(_, 50) {
        double best = 0, idx = -1;
        REP(j, 1, n) {
            ll x = (a[0] + a[j]) / 2;
            ll y = (b[0] + b[j]) / 2;
            double ret = calculate_score(x) + calculate_score(y);
            if(ret > best) {
                best = ret;
                idx = j;
            }
        }
        query.push_back({0, idx});
        do_query(a, b, 0, idx);
    }
    output(query);
    cerr << 50 * min(calculate_score(a[0]), calculate_score(b[0])) << endl;
    return 0;
}