#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<vector>
#define ll long long
using namespace std;
const int maxn=1e3+50,INF=0x3f3f3f3f;
int n,m,a[maxn][maxn],f[maxn],frt[maxn],ed[maxn],exist[maxn][maxn],vis[maxn],pos[maxn];
void Init(){
	m=0;
	for(int i=1;i<=n;++i){
		f[i]=i;pos[i]=n;frt[i]=1,ed[i]=2;vis[i]=0;
		for(int j=1;j<=n;++j)exist[i][j]=0;	
	}
}
int Find(int x){
	if(f[x]==x)return x;
	return f[x]=Find(f[x]);
}
void Merge(int x,int y){
	f[Find(x)]=Find(y);
}

int main() {
	//freopen("1.in","r",stdin);
	int T;scanf("%d",&T);
	while(T--){
		scanf("%d",&n);Init();
		if(n==1)continue;
		for(int i=1;i<=n;++i){
			for(int j=1;j<=n;++j){
				scanf("%d",&a[i][j]);
			}
			if(!exist[a[i][1]][a[i][2]])exist[a[i][1]][a[i][2]]=exist[a[i][2]][a[i][1]]=1,m++,printf("%d %d\n",a[i][1],a[i][2]);
		}
		while(1){
			if(m==n-1)goto End;
			for(int i=1;i<=n;++i){
				while(vis[a[i][pos[i]]])pos[i]--;
				vis[a[i][pos[i]]]=1;
				for(int j=1;j<=n;++j){
					if(vis[a[j][frt[j]]])frt[j]=ed[j],ed[j]++;
					while(vis[a[j][ed[j]]])ed[j]++;
					if(!exist[frt[j]][ed[j]])exist[frt[j]][ed[j]]=exist[ed[j]][frt[j]]=1,m++,printf("%d %d\n",frt[j],ed[j]);
					if(m==n-1)goto End;
				}
			}
		}
		End:;
	}
	
}