#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define maxn 1005
#define put() putchar('\n')
#define Tp template<typename Ty>
#define Ts template<typename Ty,typename... Ar>
using namespace std;
inline void read(int &x){
    int f=1;x=0;char c=getchar();
    while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}
    while (c>='0'&&c<='9') {x=x*10+c-'0';c=getchar();}
    x*=f;
}
namespace Debug{
	Tp void _debug(char* f,Ty t){cerr<<f<<'='<<t<<endl;}
	Ts void _debug(char* f,Ty x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
	Tp ostream& operator<<(ostream& os,vector<Ty>& V){os<<"[";for(auto& vv:V) os<<vv<<",";os<<"]";return os;}
	#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
}using namespace Debug;
#define fi first
#define se second
#define mk make_pair
const int mod=1e9+7;
inline int power(int x,int y=mod-2) {
	int sum=1;
	while (y) {
		if (y&1) sum=sum*x%mod;
		x=x*x%mod;y>>=1;
	}
	return sum;
}
int n,d[maxn][maxn],p[maxn][maxn];
int fa[maxn],stac[maxn],tot;
inline void dfs(int x) {
	int i;
	if (tot) {
		int id=stac[1];
		for (i=1;i<=tot;i++) if (p[x][stac[i]]<p[x][id]) id=stac[i];
//		gdb(x,id);
//		gdb(p[x][1],p[x][2],p[x][3],p[x][4]);
		fa[x]=id;		
		while (stac[tot]!=id) tot--;
	}
	stac[++tot]=x;
	for (i=2;i<=n;i++) if (!fa[d[x][i]]) dfs(d[x][i]);
}
inline void solve(void) {
	int i,j;
	read(n);
	for (i=1;i<=n;i++) fa[i]=0;
	for (i=1;i<=n;i++) 
		for (j=1;j<=n;j++) 
			read(d[i][j]),p[i][d[i][j]]=j;
	tot=0;fa[1]=n+1;dfs(1);
	for (i=2;i<=n;i++) printf("%d %d\n",i,fa[i]);
}
signed main(void){
	int T;
	read(T);
	while (T--) solve();
	return 0;
}