#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<vector>

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define pb push_back
#define sz(a) ((int)a.size())
#define mem(a, b) memset(a, b, sizeof a)
#define lson (rt << 1)
#define rson (rt << 1 | 1)
#define gmid (l + r >> 1)
#define lnum (mid - l + 1)
#define rnum (r - mid)
const int maxn = 1e2 + 5;
const int maxm = 1e6 + 5;
const int mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;

char s1[maxn][maxn], s2[maxn][maxn];
char t1[maxn][maxn], t2[maxn][maxn];
int ans[maxn], n, m, pos;

int get(char ch, int k){

    for(int i = 1; i <= m; ++i){

        if(s2[1][i] == ch){

            --k;
            if(!k){

                pos = i;
                s2[1][i] = 0;
                return i;
            }
        }
    }
    return 0;
}

int dfs(int p){

    if(p == m + 1) return 1;
    int pos, k = 1, f;
    while((pos = get(s1[1][p], k))){

//        cout << p << " " << pos << " " << k << endl;
//        for(int i = 1; i <= m; ++i) cout << s2[1][i] << " "; cout << endl;
        f = 0;
        for(int i = 2; i <= n; ++i){

            if(s2[i][pos] == s1[i][p]) continue;
            s2[1][pos] = s1[1][p]; f = 1; break;
        }
        if(f) { ++k; continue; }
        ans[p] = pos;
        if(dfs(p + 1)) return 1;
        s2[1][pos] = s1[1][p];
        ++k;
    }
    return 0;
}

int main(){

    ios::sync_with_stdio(0); cin.tie(0);
    int t; scanf("%d", &t);
    while(t--){

        scanf("%d%d", &n, &m);
        for(int i = 1; i <= n; ++i) scanf("%s%s", s1[i] + 1, s2[i] + 1);
        int f = 1;
        for(int i = 1; i <= n; ++i){

            strcpy(t1[i] + 1, s1[i] + 1);
            strcpy(t2[i] + 1, s2[i] + 1);
            t1[i][m + 1] = t2[i][m + 1] = 0;
            sort(t1[i] + 1, t1[i] + 1 + m);
            sort(t2[i] + 1, t2[i] + 1 + m);
            if(strcmp(t1[i] + 1, t2[i] + 1)) f = 0;
        }
        if(!f) { printf("-1\n"); continue; }
//        cout << " x" << endl;
        f = dfs(1);
        if(!f) { printf("-1\n"); continue; }
        for(int i = 1; i <= m; ++i) printf("%d%c", ans[i], i == m ? '\n' : ' ');
    }
    return 0;
}