#include <iostream>

using namespace std;
int a[1003];

int pos[1003][1003];
int n;
using Pair = pair<int, int>;
#include <vector>

vector<Pair> ans;

void abb(vector<int>& da) {
    if (da.size() <= 1) return;
    int a = da[0];
    int b = da[1];
    ans.push_back(make_pair(a, b));
    vector<int> ta, tb;
    ta.push_back(a);
    tb.push_back(b);
    for (int i = 2; i < da.size(); ++i) {
        int x = da[i];
        if (pos[x][a] < pos[x][b]) {
            ta.push_back(x);
        } else {
            tb.push_back(x);
        }
    }
    abb(ta);
    abb(tb);
}

void sol() {
    cin >> n;
    vector<int> tmp;
    for (int i = 1; i <= n; ++i) {
        int x;
        cin >> x;
        tmp.push_back(x);
    }
    for (int i = 2; i <= n; ++i) {
        int x, y;
        cin >> x;
        for (int j = 2; j <= n; ++j) {
            cin >> y;
            pos[x][y] = j;
        }
    }
    ans.clear();
    abb(tmp);
    for (auto x : ans) {
        if (x.first > x.second) swap(x.first, x.second);
        cout << x.first << ' ' << x.second << '\n';
    }
    // cout << '\n';
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int T;
    cin >> T;
    while (T --) {
        sol();
    }
    return 0;
}