// uzumaki naruto
#include <bits/stdc++.h>
#define each(v,c)  for(typeof((c).begin()) v = (c).begin(); v != (c).end(); ++v)
#define pb         push_back
#define mp         make_pair
#define sz(a)      ((int)(a.size()))
#define all(a)     (a).begin(), (a).end()
#define fi         first
#define se         second
#define TRACE
using namespace std;

#ifdef TRACE
#define debug(a,n)    cerr << "["; for(int i = 0; i < n; ++i) cerr << a[i] << " ";cerr << "\b]\n";
#define dbg(args...)  {debug1,args; cerr<<endl;}
#define pause()       cin.get();cin.get();

#else

#define debug(a,n)
#define dbg(args...)
#define pause()

#endif

struct debugger {
    template<typename T> debugger& operator , (const T& v) {
        cerr<<v<<" "; return *this;
    }
} debug1;

template <typename T1, typename T2>
inline ostream& operator << (ostream& os, const pair<T1, T2>& p) {
    return os << "(" << p.first << ", " << p.second << ")";
}

template<typename T>
inline ostream &operator << (ostream & os,const vector<T>& v) {
    bool first = true; os << "[";
    for (typename vector<T>::const_iterator ii = v.begin(); ii != v.end(); ++ii) {
        if(!first) os << ", ";
        os << *ii; first = false;
    }
    return os << "]";
}

typedef long long LL;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef pair<char,pii> pci;

const int NN = 2123;

vi ad[NN], con[NN];
int p[NN], d[NN][NN];

int n;
void init(){
    for(int i = 1; i <= n; ++i){
        ad[i].clear();
        con[i].clear();
        p[i] = -1;
    }
}

void dfs(int x,int f){
    p[x] = f;

    for(int i = 0; i < sz(ad[x]); ++i){
        int y = ad[x][i];
        if (y == f) break;
        if (p[y] != -1) continue;
        dfs(y,x);
    }

    for(int i = 1; i <= n; ++i){
        if (p[i] != -1) continue;
        if (d[i][x] < d[i][f])
            dfs(i,x);
    }
}

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

    init();
    for(int i = 1; i <= n; ++i){
        for(int k = 1; k <= n; ++k){
            cin >> num;
            d[i][num] = k;

            if (num == i) continue;
            if (!sz(ad[i]))
                con[num].pb(i);
            ad[i].pb(num);
        }
    }

    ad[1].pb(0);
    dfs(1,0);

    for(int i = 2; i <= n; ++i)
        cout << i << " " << p[i] << "\n";
    cout << "\n";
}

int main()
{
    ios_base::sync_with_stdio(0);
    int t; cin >> t;
    while(t--) solve();
    return 0;
}