#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <cstring>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <map>
#include <cctype>
#include <cmath>
#include <stack>
#include <sstream>
#include <list>
#include <assert.h>
#include <bitset>
#include <numeric>
#define debug() puts("++++")
#define gcd(a, b) __gcd(a, b)
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define fi first
#define se second
#define pb push_back
#define sqr(x) ((x)*(x))
#define ms(a,b) memset(a, b, sizeof a)
#define sz size()
#define be begin()
#define ed end()
#define pu push_up
#define pd push_down
#define cl clear()
#define lowbit(x) -x&x
#define all 1,n,1
#define FOR(i,n,x)  for(int i = (x); i < (n); ++i)
#define freopenr freopen("in.in", "r", stdin)
#define freopenw freopen("out.out", "w", stdout)
using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> P;
const int INF = 0x3f3f3f3f;
const LL LNF = 1e17;
const double inf = 1e20;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int maxn = 50 + 7;
const int maxm = 1e6 + 10;
const int mod = 1000000007;
const int dr[] = {-1, 1, 0, 0, 1, 1, -1, -1};
const int dc[] = {0, 0, 1, -1, 1, -1, 1, -1};
const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};
int n, m;
const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
inline bool is_in(int r, int c) {
  return r >= 0 && r < n && c >= 0 && c < m;
}
inline int readInt(){ int x;  scanf("%d", &x);  return x; }
int ans[maxn];
char a[maxn][maxn], b[maxn][maxn];
bool vis[maxn];

bool judge(int x, int y){
  for(int i = 1; i < n; ++i)
    if(a[i][x] != b[i][y])  return false;
  return true;
}

bool dfs(int cur){
  if(cur == m)  return true;
  char ch = a[0][cur];
  for(int i = 0; i < m; ++i) if(!vis[i] && b[0][i] == ch && judge(cur, i)){
    vis[i] = true;  ans[cur+1] = i+1;
    if(dfs(cur+1))  return true;
    vis[i] = false;
  }
  return false;
}

int main(){
  int T;  scanf("%d", &T);
  while(T--){
    ms(vis, 0);
    scanf("%d %d", &n, &m);
    for(int i = 0; i < n; ++i){
      scanf("%s %s", a+i, b+i);
    }
    int cnt = 0;
    for(int i = 0; i < m; ++i){
      for(int j = 0; j < m; ++j) if(!vis[j] && b[0][j] == a[0][i] && judge(i, j)){
        vis[j] = true;  ans[i+1] = j + 1; ++cnt; break;
      }
    }
    if(cnt == m){
      for(int i = 1; i <= m;++i)
        printf("%d%c", ans[i], " \n"[i==m]);
    }
    else{
      printf("-1\n");
    }
  }
  return 0;
}