#include <bits/stdc++.h>

using namespace std;
using i64 = long long;

void solve() {
    int n;
    cin >> n;

    vector<vector<int>> d(n + 1, vector<int> (n + 1));
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            cin >> d[i][j];
        }
    }

    vector<int> fa(n + 1);
    iota(fa.begin(), fa.end(), 0);
    auto find = [&] (int x) {
        while (x != fa[x]) {
            x = fa[x] = fa[fa[x]];
        }
        return x;
    };


    vector<pair<int, int>> ans;
    for (int i = n; i > 1; i--) {
        int u = d[1][i];

        int pu = find(u);
        for (int j = 1; j <= n; j++) {
            int p = find(d[u][j]);
            if (p == pu) {
                continue;
            }
            fa[pu] = p;
            ans.push_back({u, d[u][j]});
            break;
        }
    }

    for (auto [x, y] : ans) {
        cout << x << " " << y << "\n";
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t;
    cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}