#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <iomanip>

using namespace std;

const int N = 1e6+7;
int n, m, c[2];
bool bd[N];
string s;
int a[N], b[N];
void solve() {
    cin >> n >> m;
    c[0] = -1;
    c[1] = -1;

    for (int i = 0; i < n; i++) {
        bd[i] = 0;
        int cnt = 0;
        for (int j = 0; j < m; j++) {
            cin >> a[i * m + j];
            b[i * m + j] = a[i * m + j];
        }
        sort(b + i * m, b + i * (m) + m);
        for (int j = 0; j < m; j++) {
            if (a[i * m + j] != b[i * m + j]) {
                bd[i] = 1;
                if (cnt == 2) {
                    cout << "-1\n";
                    return;
                }
                if (c[cnt] != -1 && c[cnt] != j) {
                    cout << "-1\n";
                    return;
                }
                c[cnt] = j;
                cnt++;
            }
        }
    }
    if (c[0] == -1) {
        cout << "1 1\n";
        return;
    }
    for (int i = 0; i < n; i++) {
        if (a[i * m + c[0]] != a[i * m + c[1]] && !bd[i]) {
            cout << "-1\n";
            return;
        }
    }
    cout << c[0] + 1 << " " << c[1] + 1 << "\n";
}

int main()
{
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
#else
    std::ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    int t;
    cin >> t;
    while (t--) {
        solve();
        //cout << "\n";
    }
    return 0;
}