#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#define time chrono::system_clock::now().time_since_epoch().count()
#include<ext/pb_ds/tree_policy.hpp>
#define clean(x) memset(x,0,sizeof(x))
#define fil(x,n) fill(x,x+1+n,0)
#define inf 2000000009
#define maxn 1000005
// #define int long long
using namespace std;
using namespace __gnu_pbds;
mt19937_64 rnd(time);
cc_hash_table<int,int>mp;

int read() {
    int x=1,res=0;
    char c=getchar();
    while(c<'0'||c>'9') {
        if(c=='-') x=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9') {
        res=res*10+(c-'0');
        c=getchar();
    }
    return res*x;
}
set<pair<int,int>>s[1005];
int f[1005];

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

void solve() {
    int n=read();
    vector id(n+1,vector(n+1,0ll));
    for(int i=1;i<=n;i++) s[i].clear();
    for(int i=1;i<=n;i++) {
        for(int j=1;j<=n;j++) {
            int x=read();
            id[i][x]=j;
            s[i].insert({j,x});
        }
    }
    vector<pair<int,int>>ans;
    
    for(int i=1;i<=n;i++)  f[i]=i;
    while(s[1].size()>=2) {
        vector<int>res;
        for(int i=1;i<=n;i++) {
            auto u=*s[i].begin();
            auto v=*next(s[i].begin());
            if(fi(u.second)!=fi(v.second)) {
                ans.push_back({u.second,v.second});
                f[fi(u.second)]=fi(v.second);
            }
            auto z=s[i].rbegin()->second;
            res.push_back(z);
        }
        for(int i:res) {
            for(int j=1;j<=n;j++) {
                s[j].erase({id[j][i],i});
            }
        }
    }
    for(auto [u,v]:ans) {
        printf("%d %d\n",u,v);
    }
}

signed main()
{
    int t=read();
    while(t--) solve();
    return 0;
}