#include <bits/stdc++.h>

using namespace std;

int f[55][55];
int p[55];
char a[60], b[60];
bool vis[55];

int main()
{
    int T, n, m;
    scanf("%d", &T);
    while (T--)
    {
        memset(f, 0, sizeof(f));
        scanf("%d%d", &n, &m);
        for (int i = 0; i < n; i++)
        {
            scanf(" %s %s", a + 1, b + 1);
            for (int j = 1; j <= m; j++)
            {
                for (int k = 1; k <= m; k++)
                {
                    if (a[j] == b[k])
                    {
                        f[j][k]++;
                    }
                }
            }
        }
        memset(vis, false, sizeof(vis));
        bool check = true;
        for (int i = 1; i <= m; i++)
        {
            p[i] = -1;
            for (int j = 1; j <= m; j++)
            {
                if (vis[j]) continue;
                if (f[i][j] == n)
                {
                    p[i] = j;
                    vis[j] = true;
                    break;
                }
            }
            if (p[i] == -1) check = false;
        }
        if (!check) printf("-1\n");
        else
        {
            printf("%d", p[1]);
            for (int i = 2; i <= m; i++) printf(" %d", p[i]);
            printf("\n");
        }
    }
    return 0;
}