#include <bits/stdc++.h>

using i64 = long long;

struct DSU {
    std::vector<int> f;

    DSU(int n): f(n) {std::iota(f.begin(), f.end(), 0); }

    int find(int x) {
        if(x != f[x]) f[x] = find(f[x]);
        return f[x];
    }

    bool same(int x, int y) {
        return find(x) == find(y);
    }

    bool merge(int x, int y) {
        x = find(x), y = find(y);
        if(x == y) return false;
        f[x] = y;
        return true;
    }

};

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

    DSU dsu(n + 1);
    std::set<std::pair<int, int>> edges;
    std::vector<std::vector<int>> g(n, std::vector<int>(n));
    for(int i = 0; i < n; i ++ ) {
        for(int j = 0; j < n; j ++ ) {
            std::cin >> g[i][j];
        }
        int x = g[i][0], y = g[i][1];
        if(x > y) std::swap(x, y);
        edges.insert({x, y});
        dsu.merge(x, y);
    }

    std::map<std::pair<int, int>, int> mp;
    std::set<std::pair<int, int>> vis;
    for(int i = 0; i < n; i ++ ) {
        vis.clear();
        for(int j = 1; j < n; j ++ ) {
            int x = g[i][j - 1], y = g[i][j];
            int u = dsu.find(x), v = dsu.find(y);
            if(u != v && !vis.count({u, v})) {
                mp[{u, v}] = y;
                vis.insert({u, v});
            }
        }
    }

    for(auto [o, w] : mp) {
        auto [u, v] = o;
        int x = w, y = mp[{v, u}];
        if(x > y) std::swap(x, y);
        edges.insert({x, y});
    }

    for(auto [x, y] : edges) {
        std::cout << x << ' ' << y << '\n';
    }

}

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

    int T = 1;
    std::cin >> T;

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

    return 0;
}