#include<bits/stdc++.h>
using namespace std;
inline int read() {
    int x = 0;
    char c = getchar();
    bool f = 0;
    while(!isdigit(c)) f |= (c == '-'), c = getchar();
    while(isdigit(c)) x = (x * 10) + (c ^ 48), c = getchar();
    return f ? -x : x;
}
const int maxn = 1005;
int T, n;
int D[maxn][maxn], Vst[maxn];
int main() {
//    freopen("G.in", "r", stdin);
//    freopen("G.out", "w", stdout);
    T = read();
    while(T--) {
        n = read();
        for(register int i = 1; i <= n; ++i) Vst[i] = 0;
        for(register int i = 1; i <= n; ++i)
            for(register int j = 1; j <= n; ++j) D[i][j] = read();
        for(register int i = n; i > 1; --i) {
            int x = D[1][i];
            Vst[x] = 1;
            for(register int j = 2; j <= n; ++j)
                if(!Vst[D[x][j]]) printf("%d %d\n", x, D[x][j]);
        }
    }
    return 0;
}