#include <bits/stdc++.h>

using u32 = unsigned;
using i64 = long long;
using u64 = unsigned long long;

void solve() {
    int n;
    std::cin >> n;
    std::vector<std::vector<int>> a(n + 1, std::vector<int>(n + 1));
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            std::cin >> a[i][j];
        }
    }
    std::vector<int> vis(n + 1, false);
    std::vector<std::array<int, 2>> ans;
    int x = a[1][n];
    for (int i = 2; i <= n; i++) {
        vis[x] = true;
        for (int j = 1; j <= n; j++) {
            if (!vis[a[x][j]]) {
                int y = a[x][j];
                ans.push_back({x, y});
                break;
            }
        }
        for (int j = n; j >= 1; j--) {
            if (!vis[a[x][j]]) {
                x = a[x][j];
                break;
            }
        }
    }
    for (auto v: ans) {
        std::cout << v[0] << " " << v[1] << "\n";
    }
}

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

    int T = 1;
    std::cin >> T;
    while (T--) {
        solve();
    }

    return 0;
}