#include<bits/stdc++.h>
using namespace std;

char s1[60][60],s2[60][60];
int ans[60],flag;
int n,m;
int vs[60];

bool check(int x,int y)
{
    for (int i=0;i<n;i++)
    {
        if (s1[i][x]!=s2[i][y]) return true;
    }
    return false;
}

void dfs(int p)
{
    if (flag) return ;
    if (p==m)
    {
        flag = 1;
        return ;
    }
    for (int i=0;i<m;i++)
    {
        if (vs[i]) continue;
        if (check(p,i)) continue;
        ans[p]=i+1;
        vs[i]=1;
        dfs(p+1);
        vs[i]=0;
        return ;
    }
}

int main()
{
    int t;
    cin>>t;
    while (t--)
    {

        scanf("%d %d",&n,&m);
        for (int i=0;i<n;i++) scanf("%s %s",s1[i],s2[i]);
        memset(vs,0,sizeof(vs));
        flag = 0;
        dfs(0);
        if (flag==0)
        {
            cout<<"-1"<<endl;
            continue;
        }
        for (int i=0;i<m-1;i++) cout<<ans[i]<<" ";
        cout<<ans[m-1]<<endl;
    }
}