#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cctype>
 
#include <algorithm>
#include <random>
#include <bitset>
#include <queue>
#include <functional>
#include <set>
#include <map>
#include <vector>
#include <chrono>
#include <iostream>
#include <limits>
#include <numeric>
 
#define LOG(FMT...) fprintf(stderr, FMT)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int N = 52;

int n;
bool vis[N];
bool f[N][N];
char s[N], t[N];
int match[N], rp[N];

bool dfs(int u) {
  vis[u] = true;
  for (int i = 1; i <= n; ++i) {
    if (f[u][i]) {
      if (!match[i] || (!vis[match[i]] && dfs(match[i]))) {
        match[i] = u;
        return true;
      }
    }
  }
  return false;
}

void solve() {
  int m;
  scanf("%d%d", &m, &n);
  for (int i = 1; i <= n; ++i) fill(f[i] + 1, f[i] + n + 1, true);
  memset(match, 0, sizeof(match));
  bool flag = true;
  while (m--) {
    scanf("%s%s", s + 1, t + 1);
    for (int i = 1; i <= n; ++i)
      for (int j = 1; j <= n; ++j)
        if (s[i] != t[j])
          f[i][j] = false;
    sort(s + 1, s + n + 1);
    sort(t + 1, t + n + 1);
    if (!equal(s + 1, s + n + 1, t + 1))
      flag = false;
  }
  if (!flag) {
    puts("-1");
    return;
  }
  for (int i = n; i; --i) {
    memset(vis, 0, sizeof(vis));
    if (!dfs(i)) {
      puts("-1");
      return;
    }
  }
  for (int i = 1; i <= n; ++i)
    rp[match[i]] = i;
  for (int i = 1; i < n; ++i)
    printf("%d ", rp[i]);
  printf("%d\n", rp[n]);
}

int main() {
  int t;
  scanf("%d", &t);
  while (t--) solve();
  return 0;
}