#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define PII pair<int,int>
#define all(x) (x).begin(),(x).end()
const int N = 5e5+10;
void solve(){
    int n;cin>>n;
    int a[n+1][n+1];
    vector<int>pos(n+1);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cin>>a[i][j];
            pos[a[i][j]]=max(pos[a[i][j]],j);
        }
    }
    int mn=1e9,ans=1;
    for(int i=1;i<=n;i++)if(pos[i]<mn)ans=i,mn=pos[i];
    for(int i=1;i<=n;i++)if(i!=ans)cout<<i<<' '<<ans<<endl;
}
signed main(){
    ios::sync_with_stdio(false);cin.tie(0);
    int t=1;cin>>t;
    while(t--)solve();
}