#include<bits/stdc++.h>
using namespace std;
char s1[22][55], s2[22][55];
int main(){
    int T;
    scanf("%d", &T);
    while(T--){
        int n, m;
        scanf("%d%d", &n, &m);
        for(int i = 0; i < n; ++i){
            scanf("%s%s", s1[i], s2[i]);
        }
        vector<int> vis(m+1, 0);
        vector<int> ans;
        for(int i = 0; i < m; ++i){
            for(int j = 0; j < m; ++j){
                if(vis[j]) continue;
                bool ok = true;
                for(int k = 0; k < n; ++k){
                    if(s1[k][i] != s2[k][j]) {
                            ok = false;break;
                    }
                }
                if(ok){
                        vis[j] = 1;
                        ans.push_back(j);
                        break;
                }
            }
        }
        if(ans.size() != m) printf("-1\n");
        else{
            for(int i = 0; i < ans.size(); ++i){
                if(i) printf(" ");
                printf("%d", ans[i]+1);
            }
            puts("");
        }
    }
    return 0;
}